Issue
Document fails to transmit document, as listed in the history of the envelope/document.
Error Code
Nintex AssureSign servers will report all errors, from all locations, including as shared from your servers in the document history. Because it's relevant to the final document and the correctness of the history of collecting the signatures and the full interactions of the document for legal reasons, you may see something that references your servers as a failure in the document history, as in the error listed as example below:

Resolution
We suggest that you reach out to your IT team to take a look at the server logs to discover what was going on so they can help you resolve this issue. Nintex AssureSign does not have access to these, so it must be done by them.
