# jsonschema.exceptions.RefResolutionError:

**URL:** <https://community.blockcerts.org/t/jsonschema-exceptions-refresolutionerror/1330>\
**Category:** Support\
**Created:** [September 5, 2018, 12:26pm UTC](https://community.blockcerts.org/t/jsonschema-exceptions-refresolutionerror/1330 "2018-09-05T12:26:17Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Taibah](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@Taibah](https://community.blockcerts.org/u/Taibah)\
**Post date:** [September 5, 2018, 12:26pm UTC](https://community.blockcerts.org/t/jsonschema-exceptions-refresolutionerror/1330/1 "2018-09-05T12:26:17Z")

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Hello,

Everytime i want to issue a certificate i get this error hope someone can help me.

jsonschema.exceptions.RefResolutionError: HTTPSConnectionPool(host=‘[www.blockcerts.org](http://www.blockcerts.org)’, port=443): Max retries exceeded with url: /schema/2.0/recipientSchema.json (Caused by SSLError(SSLError(1, u’[SSL: TLSV1\_ALERT\_PROTOCOL\_VERSION] tlsv1 alert protocol version (\_ssl.c:590)’),))

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**Author:** ![Hugo](https://sea2.discourse-cdn.com/flex016/user_avatar/community.blockcerts.org/hugo/32/449_2.png) [@Hugo](https://community.blockcerts.org/u/Hugo)\
**Post date:** [September 5, 2018, 11:56pm UTC](https://community.blockcerts.org/t/jsonschema-exceptions-refresolutionerror/1330/2 "2018-09-05T23:56:14Z")

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Hello @Taibah

Maybe you are using **python2** when you need **python3**.  
Make sure you are using a virtualenv as explained in the recommendations here: [https://github.com/blockchain-certificates/cert-issuer/blob/master/docs/virtualenv.md](https://github.com/blockchain-certificates/cert-issuer/blob/master/docs/virtualenv.md)

I saw a similar error here: [Error installing cert-issuer on ethereum](https://community.blockcerts.org/t/error-installing-cert-issuer-on-ethereum/1091/10) (which I think could have been solved by installing **python3-dev** ).