The handlers are so precious advice, thank you!

It allowed me to discover that the sid has hidden control chars before the 32 chars, so I fixed that.
BUT that does not fix the issue.

However after sending the first sid for authentication, the server is sending a cookie with another sid, so I need to probably deal with that. Also, I need to do the same handler trick to the python code, and that will definitively help to solve the problem.

EDIT: it was the cookies. Adding a cookie jar did the trick!

Thank you!