"There was a problem accessing the Map Manager" from combat scripts

I'm returning to Mafia after a bit of a hiatus and I've tracked down most of my scripting errors but I still get "There was a problem accessing the Map Manager" at the start of each combat. I'm using WHAM, but it's updated via SVN so maybe something else I added somewhere?

A little further digging, it's from trying to update the batfactors map. https://zachbardon.com/mafiatools/autoupdate.php?f=batfactors&act=getver gives me a normal response from a browser but Mafia is seeing "".

To answer my own question: zachbardon.com now uses LetsEncrypt for its TLS cert, and my Java was too old to trust that CA root. I tried manually importing the CA root cert but that didn't work (I suspect it should have but maybe I did something wrong), but upgrading to a newer JVM fixed it entirely.