Thanks for your quick answer 
Yup, I verified the private key. I use bitcoin-cli to directly dump it into the file. For my public key it is:
~# bitcoin-cli dumpprivkey "2MwBERpNv7JJaW4nVUbQncXjFjG1nFKLYEp" > /etc/cert-issuer/pk_issuer.txt
As a result, pk_issuer.txt is created and contains a 52 characters string (I double checked it and it is conform to what comes out the standard output. Also, no space is hidden at the end of the line). I also created other adresses, sent funds, updated the private key accordingly but still the same exception is raised. There is something I’m missing…
The only condition for it to work is that the private key matches the public key? Doesn’t the public key have to match something else? Or doesn’t some parameter have to be set to something special?
Here is the log that appears with the trace:
WARNING - Your app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
INFO - This run will try to issue on the bitcoin_testnet chain
INFO - Set cost constants to recommended_tx_fee=0.000600,min_per_output=0.000028,satoshi_per_byte=250
INFO - Set cost constants to recommended_tx_fee=0.000600,min_per_output=0.000028,satoshi_per_byte=250
INFO - Processing 2 certificates
INFO - Processing 2 certificates
INFO - Processing 2 certificates under work path=/etc/cert-issuer/data/work
INFO - Processing 2 certificates under work path=/etc/cert-issuer/data/work
INFO - Total cost will be 133500 satoshis
INFO - Total cost will be 133500 satoshis
INFO - Starting finalizable signer
INFO - Starting finalizable signer
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
INFO - Stopping finalizable signer
INFO - Stopping finalizable signer
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
INFO - here is the op_return_code data: 96b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec34
INFO - here is the op_return_code data: 96b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec34
INFO - Unsigned hextx=0100000001fea7ff632a1f4fbaa69ffde7e94351ded43256a43f0a946bfb42946210ac85d70200000000ffffffff02e0604b000000000017a9142b1f34ef778f4e9efa9e36204592c6d029901116870000000000000000226a2096b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec3400000000
INFO - Unsigned hextx=0100000001fea7ff632a1f4fbaa69ffde7e94351ded43256a43f0a946bfb42946210ac85d70200000000ffffffff02e0604b000000000017a9142b1f34ef778f4e9efa9e36204592c6d029901116870000000000000000226a2096b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec3400000000
INFO - Preparing tx for signing
INFO - Preparing tx for signing
INFO - Starting finalizable signer
INFO - Starting finalizable signer
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
ERROR - Unable to sign transaction. hextx=0100000001fea7ff632a1f4fbaa69ffde7e94351ded43256a43f0a946bfb42946210ac85d70200000000ffffffff02e0604b000000000017a9142b1f34ef778f4e9efa9e36204592c6d029901116870000000000000000226a2096b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec3400000000
ERROR - Unable to sign transaction. hextx=0100000001fea7ff632a1f4fbaa69ffde7e94351ded43256a43f0a946bfb42946210ac85d70200000000ffffffff02e0604b000000000017a9142b1f34ef778f4e9efa9e36204592c6d029901116870000000000000000226a2096b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec3400000000
INFO - Stopping finalizable signer
INFO - Stopping finalizable signer
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
WARNING - app is configured to skip the wifi check when the USB is plugged in. Read the documentation to ensure this is what you want, since this is less secure
Traceback (most recent call last):
File "/usr/local/bin/cert-issuer", line 11, in <module>
sys.exit(cert_issuer_main())
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/__main__.py", line 17, in cert_issuer_main
issue_certificates.main(parsed_config)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/issue_certificates.py", line 36, in main
return issue(app_config, certificate_batch_handler, transaction_handler)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/issue_certificates.py", line 22, in issue
tx_id = issuer.issue(app_config.chain)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/issuer.py", line 27, in issue
txid = self.transaction_handler.issue_transaction(blockchain_bytes)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/blockchain_handlers/bitcoin/transaction_handlers.py", line 56, in issue_transaction
signed_tx = self.sign_transaction(prepared_tx)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/blockchain_handlers/bitcoin/transaction_handlers.py", line 92, in sign_transaction
signed_tx = signer.sign_transaction(prepared_tx)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/models.py", line 84, in sign_transaction
return self.signer.sign_transaction(self.wif, transaction_to_sign)
File "/usr/local/lib/python3.6/dist-packages/cert_issuer/blockchain_handlers/bitcoin/signer.py", line 35, in sign_transaction
raise UnableToSignTxError('Unable to sign transaction')
cert_issuer.errors.UnableToSignTxError: Unable to sign transaction
and here is the transaction decoded with blockcypher
{
"addresses": [
"35d2N5StVqoEJH9woTnuzajzWuocS3Wrfy"
],
"block_height": -1,
"block_index": -1,
"confirmations": 0,
"data_protocol": "unknown",
"double_spend": false,
"fees": 0,
"hash": "73f405b87f40aa43c7a588f1b64d7f23e8289e9e5994e7895d881f3d7f3f3b0a",
"inputs": [
{
"age": 0,
"output_index": 2,
"prev_hash": "d785ac10629442fb6b940a3fa45632d4de5143e9e7fd9fa6ba4f1f2a63ffa7fe",
"script_type": "empty",
"sequence": 4294967295
}
],
"outputs": [
{
"addresses": [
"35d2N5StVqoEJH9woTnuzajzWuocS3Wrfy"
],
"script": "a9142b1f34ef778f4e9efa9e36204592c6d02990111687",
"script_type": "pay-to-script-hash",
"value": 4940000
},
{
"addresses": null,
"data_hex": "96b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec34",
"script": "6a2096b798b6be8af088b4194af4f7fdc3f880f4f1cfe6a04f482465d8f5f675ec34",
"script_type": "null-data",
"value": 0
}
],
"preference": "low",
"received": "2019-03-14T13:12:07.850995292Z",
"relayed_by": "54.227.204.11",
"size": 126,
"total": 4940000,
"ver": 1,
"vin_sz": 1,
"vout_sz": 2
}
