If you don't know, you may miss some knowledge.
Your error is:
Could not connect to ssl://dokuwiki.home.arpa:443
You need to test the connection from the source to the target and because it's SSL, it needs the certificates.
Use curl in your source (main) server to test if you can connect with SSL against the replica.
If you can't, you have a certificate problem.
You can also try with another SSL client such as openssl.
I have no idea how php connect via SSL on port but their is some configuration on that in the php.ini.
All the best