Cross RP has been broken by 8.1. Blizzard removed one of the key commands needed to make the addon run; right now no addon can read guild or community chats.
I’ve created a couple of RP chat channels if anyone would like to use them for cross-RP communication. Don’t forget you can move community channels into your main chat window for ease of use!
The maker of the addon has put up a post on General if folks would like to weigh in on the subject.