Trying to help my member with his problem...
Using Jamroom
Thanks for giving us the exact wording: "You do not have permission to access this server"
That wording appears in 5 locations in jamroom, 4 of them are in the jrBanned module and 1 is in jrUser.
in jrUser its a check for banned 'bot's that are banned via that jrBanned module, so all those messages are related to something setup in
DASHBOARD -> ADMIN -> BANNED ITEMS
Take a look at what you've got setup there and see if anything could match the user your interested in.