So, from what I can gather, the mod really hates running on dedicated servers.
I've got some of the error log when creating a portal, as the portal appears black but you can't go through it and that's it, I've also noted that on reload of the server this causes it to crash when a player joins. I've tried removing the mods that it lists here, but once I do that, the list changes. to note, I removed Astral Sorcery, Zombie Awareness (has problems with it's required util) and a few other things.
BetterPortals-Error.txt

Duplicate of #38