# How to create a valid issuer?

**URL:** <https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113>\
**Category:** Support\
**Created:** [March 10, 2022, 10:49pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113 "2022-03-10T22:49:53Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![juaneltemible](https://avatars.discourse-cdn.com/v4/letter/j/898d66/32.png) [@juaneltemible](https://community.blockcerts.org/u/juaneltemible)\
**Post date:** [March 10, 2022, 10:49pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/1 "2022-03-10T22:49:53Z")

</div>

Hello, I’m having a problem with the validation of a certificate, I’m able to issue a certificate to the ethereum ropsten chain, but when I try to validate it I keep getting this error:

 ![Screen Shot 2022-03-10 at 4.41.20 p.m.](https://us1.discourse-cdn.com/flex016/uploads/blockcerts/original/1X/8afc7149e0cae481aa43fe66abc1b0252ea2fb0e.png)

I’ve also tried changing the issuer but I get instead an error like this at the verifier:

ErrorNot a valid Blockcerts credential. Please check with the issuer or recipient that has provided this credential.

I’ll leave here also the link to [my issuer json](https://www.tech-mindfactory.com/tmfissuer.json)

I would like to know what is wrong with my issuer profile.

I would appreciate a lot any kinds of help!!

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [March 14, 2022, 2:04pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/2 "2022-03-14T14:04:50Z")

</div>

The error you are getting is because the transaction data (the blockchain transaction that is) cannot be retrieved.  
It is either because you are testing your cert too early after issuance and the transaction has not propagated on the blockchain (not enough confirmations) or because the transaction referenced does not exist but that would be quite surprising since I am not aware of such a (major) issue.

As far as I can tell your issuer profile looks correct.

When this error comes up

```auto
ErrorNot a valid Blockcerts credential. Please check with the issuer or recipient that has provided this credential.

```

You may have access to a more explicit, technical error in the developer console of your browser. You could have a look at that.

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 1, 2022, 7:57am UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/3 "2022-11-01T07:57:47Z")

</div>

@lemoustachiste @juaneltemible

i’m also facing the similar issue

In the console, I can see Didn’t recognize chain value.

I’m using ethereum\_sepolia chain

 ![Screenshot 2022-11-01 at 11.53.26 AM](https://us1.discourse-cdn.com/flex016/uploads/blockcerts/original/1X/dc139e283f76546d6ee4def7010423419819bbfc.png)

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 2, 2022, 11:29am UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/4 "2022-11-02T11:29:46Z")

</div>

hm it should be supported: [explorer-lookup/blockchains.ts at master · blockchain-certificates/explorer-lookup · GitHub](https://github.com/blockchain-certificates/explorer-lookup/blob/master/src/constants/blockchains.ts#L64)

Could you share your cert so I can investigate?

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 2, 2022, 11:57am UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/6 "2022-11-02T11:57:05Z")

</div>

@lemoustachiste  
Here is the certificate content

{“@context”: [“[https://www.w3.org/2018/credentials/v1](https://www.w3.org/2018/credentials/v1)”, “[https://w3id.org/blockcerts/v3](https://w3id.org/blockcerts/v3)”], “type”: [“VerifiableCredential”, “BlockcertsCredential”], “issuer”: “[https://raw.githubusercontent.com/sreenumalae/DataStorage/main/testissuer.json](https://raw.githubusercontent.com/sreenumalae/DataStorage/main/testissuer.json)”, “issuanceDate”: “2022-10-31T11:31:03Z”, “id”: “urn:uuid:af05c673-02f2-430f-aefc-5256f053c39a”, “credentialSubject”: {“id”: “ecdsa-koblitz-pubkey:mtr98kany9G1XYNU74pRnfBQmaCg2FZLmc”, “alumniOf”: {“id”: “[https://www.human-logic.com/](https://www.human-logic.com/)”}}, “proof”: {“type”: “MerkleProof2019”, “created”: “2022-10-31T12:05:00.478050”, “proofValue”: “znKD4YGVqA8textxikpfbsSQxuWguMznNeK95EspXveCLCWTH9xVEyuRBGUL1qrGrvRJDUDrSrdP5nxZWwZDWPFMru2xHaLJaEgX7QpL92giUyTYLviqxsU3snV2qrpGGtsGYp1CpMSdsWRYCqkbnBT5s9Yh6q4j8HkYCC5Tq9AAezkiaqcMBUcUDMTkrrou4zPY5nEoRqmZCR4aq5gexwCKPahJfpCVp7hG1q84JjoVjRybzWXANbCaQqJQN6VZ5bn1My9kUwYYP6g8EByfTK9nvjraWsyVwjT9eZDWgKVU6VxtpmmNAY8HbiM”, “proofPurpose”: “assertionMethod”, “verificationMethod”: “URL”}}

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 2, 2022, 12:57pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/7 "2022-11-02T12:57:56Z")

</div>

it looks like your proof is malformed:

```auto
{
      path: [],
      merkleRoot: '635a5828df1cbd886111e9ffee82c1c9072a12f5ae82fa6300115eb3de3d7f4c',
      targetHash: '635a5828df1cbd886111e9ffee82c1c9072a12f5ae82fa6300115eb3de3d7f4c',
      anchors: [
        'blink:eth:undefined:0x8b4db734457fe3c5d590dc38040a9573ae5a9f8201c5b3d0b75019d43450ada6'
      ]
    }

```

the anchor does not reference Sepolia but undefined.

So it could be an issue with cert-issuer maybe? How is your conf.ini defined?

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 2, 2022, 1:19pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/8 "2022-11-02T13:19:32Z")

</div>

My conf.ini in cert-issuer

issuing\_address = 0x4d6919d34132C6963cfEe665309C6079822795BB

verification\_method = URL

chain= ethereum\_sepolia

usb\_name = \</Volumes/path-to-usb/\>

key\_file = /home/azureuser/blockchain\_attempt2/cert-issuer/data/keyfile.txt

unsigned\_certificates\_dir=/home/azureuser/blockchain\_attempt2/cert-tools/sample\_data/unsigned\_certificates

blockchain\_certificates\_dir=/home/azureuser/blockchain\_attempt2/cert-tools/sample\_data/signed

work\_dir=/home/azureuser/blockchain\_attempt2/cert-issuer/data/work

no\_safe\_mode

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 2, 2022, 1:28pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/9 "2022-11-02T13:28:48Z")

</div>

ok let me check then

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 2, 2022, 1:39pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/10 "2022-11-02T13:39:38Z")

</div>

so I’ve got an error and I cannot issue on sepolia anyway:

```auto
raise UnknownChainError(app_config.chain)
cert_core.UnknownChainError: Chain.ethereum_sepolia

```

How did you issue the certificate?

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 2, 2022, 2:01pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/11 "2022-11-02T14:01:53Z")

</div>

Ok I think I’m getting the above error due to some python shenanigans on my machine. Trying to sort it out

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 2, 2022, 2:34pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/12 "2022-11-02T14:34:51Z")

</div>

Ok so it looks like cert-issuer works ok, here is my anchor for an issuance on sepolia:

blink:eth:sepolia:0x1f615470024000c3ab532ed74c5a60b8f6c2feb6489a67be20f103831996f9ab

you should maybe try and issue again

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 3, 2022, 11:03am UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/13 "2022-11-03T11:03:46Z")

</div>

@lemoustachiste

I tried to install it again and followed the whole process again from the fist.

Successfully I created both unsigned and signed certificates and the issue still remains same.

Here is my signed certificate:

`{"@context": ["https://www.w3.org/2018/credentials/v1", "https://w3id.org/blockcerts/v3"], "type": ["VerifiableCredential", "BlockcertsCredential"], "issuer": "https://raw.githubusercontent.com/sreenumalae/DataStorage/main/testissuer.json", "issuanceDate": "2022-11-03T09:28:54Z", "id": "urn:uuid:004873c9-c21b-4f33-aae6-714eb964f626", "credentialSubject": {"id": "ecdsa-koblitz-pubkey:mkwntSiQmc14H65YxwckLenxY3DsEpvFbe", "alumniOf": {"id": "https://www.human-logic.com/"}}, "nonce": "1", "proof": {"type": "MerkleProof2019", "created": "2022-11-03T10:54:42.597456", "proofValue": "z9nmN4tsD8AYm9oa7cgcUrCN4Lqecj7HMdoAz1UbYbw8PLrmc2GoFJiV5bk9xXcWDbKsidjXSBoBsp7DqZX4WDfPS3sfTyt9vKrCE2NYjxS34TEmBhVW9uirAhM6uLq9QtxjLX8xu3wTaGSZrf8SHiHY9fUEVm9JufBjvD7axpkdGiEc48yQLynnVYEUtBZWTkVmwTkPg2XQWUNE6hPr9CcpmXBF5VBgxqaps9pyZmzaBBrGuiVJ7p3BD5c8d7C4AA2rbVPhPXTjK34ddVzDTy7W2XYfDrFE1jHmF87sYUzeVEWkwTzrNMQ5xWhwjvS9TwUo78272FgeW4TsKjZy7hyQ8tcAfeL5SH23uJetwMSn8qoQCJ9YngcWF3BqKrBGy6FZvjATvLHdGuCBjPcL5BhCPhP", "proofPurpose": "assertionMethod", "verificationMethod": "URL"}}`

anchor for an issuance on sepolia

INFO - merkle\_json: {‘path’: [{‘right’: ‘94b0236ef84cb4f5a32e5d66b47424d6d068908d3e6bc6eea13c35aaf4211c1b’}], ‘merkleRoot’: ‘a845bf3d74a5aa78b5ade32c44583640645b4459e651b4314830afb5b439dab0’, ‘targetHash’: ‘8885070fede3b20e463cc225436d604d9f312789fbbfe498270e1f130ade74d4’, ‘anchors’: [‘blink:eth:sepolia:0xe7a23bbb0150c8d0594f4241c29fb7da946daad7deac4a9644f1469d51351546’]}

INFO - merkle\_json: {‘path’: [{‘left’: ‘8885070fede3b20e463cc225436d604d9f312789fbbfe498270e1f130ade74d4’}], ‘merkleRoot’: ‘a845bf3d74a5aa78b5ade32c44583640645b4459e651b4314830afb5b439dab0’, ‘targetHash’: ‘94b0236ef84cb4f5a32e5d66b47424d6d068908d3e6bc6eea13c35aaf4211c1b’, ‘anchors’: [‘blink:eth:sepolia:0xe7a23bbb0150c8d0594f4241c29fb7da946daad7deac4a9644f1469d51351546’]}

INFO - Broadcast transaction with txid 0xe7a23bbb0150c8d0594f4241c29fb7da946daad7deac4a9644f1469d51351546

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 3, 2022, 1:21pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/14 "2022-11-03T13:21:51Z")

</div>

@lemoustachiste  
As i can see the issuance is also similar to the one you created.

Kindly help me out with this [issue](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/13)

Thanks in Advance

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 3, 2022, 3:07pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/15 "2022-11-03T15:07:56Z")

</div>

I’ve finally figured out the issue, I’m working on the fix

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 3, 2022, 4:30pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/16 "2022-11-03T16:30:41Z")

</div>

I’m still facing issues, I think I should be able to resolve by tomorrow

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 4, 2022, 6:26am UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/17 "2022-11-04T06:26:02Z")

</div>

ok Thanks @lemoustachiste

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 4, 2022, 3:47pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/18 "2022-11-04T15:47:08Z")

</div>

it’s in PR, but some tests on the master branch that were working 2 weeks ago are now failing and I need to investigate why.

So the code in this PR will verify a Sepolia or Goerli anchored cert: [fix(Sepolia): ensure sepolia anchored verification by lemoustachiste · Pull Request #1447 · blockchain-certificates/cert-verifier-js · GitHub](https://github.com/blockchain-certificates/cert-verifier-js/pull/1447/)

If you feel bold enough you can use this branch, either directly locally with a copy of CVJS, or installing it to a local copy of blockcerts-verifier. At least that’s a way to have you unblocked while I figure out why those tests are suddenly failing.

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 4, 2022, 7:10pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/19 "2022-11-04T19:10:01Z")

</div>

Thank you @lemoustachiste

I will try to use the PR and install it in my local drive.

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<div class="post-metadata">

**Author:** ![lemoustachiste](https://avatars.discourse-cdn.com/v4/letter/l/7c8e57/32.png) [@lemoustachiste](https://community.blockcerts.org/u/lemoustachiste)\
**Post date:** [November 7, 2022, 4:52pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/20 "2022-11-07T16:52:21Z")

</div>

Blockcerts Verifier has been updated, and it’s live on [blockcerts.org](http://blockcerts.org)

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<div class="post-metadata">

**Author:** ![sreenumalae](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/sreenumalae/32/773_2.png) [@sreenumalae](https://community.blockcerts.org/u/sreenumalae)\
**Post date:** [November 8, 2022, 8:06pm UTC](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113/21 "2022-11-08T20:06:49Z")

</div>

Thanks @lemoustachiste for the update \<3

[Next page](https://community.blockcerts.org/t/how-to-create-a-valid-issuer/3113.md?page=2)