Hi tried logging in to a chat room yesterday and got this message
Can't join channel(+b), can some tell me what that means? Thanks in advance.

Your host is banned, but maybe it's not you that made something wrong, someone on the same ISP maybe have done something, you wont be able to get back in untill your ban is removed by a channel op..

Got it , thank you.

Some IRCds additionally support using the /mode #<Channek> b to view all channel bans.

However, some of them require you to be in the channel in order for it to work.