I have fixed this issue on my end; it may be an erroneous bug on the upgrade portion.
About the time that I upgraded from stretch->buster, I also turned on the SSL connections on slapd. It seems that earlier versions of fusiondirectory will connect to localhost just fine, but because of the SSL cert it seems like it was failing. Bad connection string: ldap://localhost:389 Good connection string: ldap://ldap.example.com:389 Regardless, the error that comes back is still completely useless, since it does not tell you anything about possible SSL errors. -Robert Middleton
