The HTTP request with your answer must be sent before the time limit is up.
In this time you have to send your HTTP with authentication to verify that its you and there must be the correct answer.
From what I gather, some Python libs function too slowly for this to be effective, so it may be the lib you’re using OR there is an error in the decrypted text (such as an extra space of some kind or another mishap).
Feel free to PM me if your still stuck. :)