Serious issues with mods

Ever since v244, new mods won’t work. Anything I create causes issues and nobody can connect (assertion errors or connection timeouts). Even on a fresh mod, with nothing in it, nobody can connect except for me. Two things I notice:

Verifying ARK will result in 3 or 4 files that need to be replaced.

Verifying UE4 results in files being downloaded as well.

One time after verifying ARK, someone could connect to my non-dedicated server.

What could I be overlooking?

You most likely have made changes that the code executes server side and people aren’t updating the mod.

Reset ModGUID BEFORE cooking to force them onto the new files.