fetch post to https server

Hello. I’m trying to post data to a simple https server I created in python. I am able to get and post to this server using curl on my linux machine, but when I try to connect using my mikrotik’s fetch tool I get this:

[admin@MikroTik] > /tool fetch mode=https url="https://10.19.8.69/" port=4443 http-method=post http-header-field="Content-Type: text/html" http-data="hi" check-certificate=no

status: failed

failure: ssl connection error: ssl: fatal alert received (6)

This happens even if I send a get request to my https server. I’m using a self-signed certificate generated using openssl and my https server is using TLS.

Is there any documentation on ssl error codes?