DISCLAIMER: GROUPMANAGER ISN'T MY PLUGIN, AND I TAKE NO CREDIT FOR THE PLUGIN ITSELF. IT IS JUST SOME FIXES.

Well, Since groupmanager has released (Unofficially), There always were bugs which Essentials aren't fixing.
Well... IDK what about it.....

Q: I set up groupmanager, but the prefixes aren't showing up.
Fix: There may be plenty of reasons why this is happening. The main reasons are:
1. Check: Is Essentials Chat or any chat manager plugin is installed? (Most Common)
2. is PermissionEX / Any other Rank managing plugin is istalled too. (Common)
3. Did you download the ORIGINAL / Latest Groupmanager? Please consider downloading it from here: kHobbit's official release.
4. If none of the above fixed it, Please consider sending kHobbit an PM on SpigotMC.

Q: Ask in the comments
Fix: And i will awnser.