Forums mIRC Help Disconnected almost immediately from channels

I need some help. I have been using mIRC for almost 7 years. Yesterday my internet provider changed me from DSL service to WiFi. When I went to log into the mIRC today I was given an error message that I couldn't log into any server I tried. I fixed this by letting the mIRC past my firewall. Now I can connect to IRC okay and get to a channel but I almost immediately get disconnected from that channel. I tried several channels with the same result. I have reloaded mIRC today and the problem still exists. All seems okay, I remain connected to the server (at least it tells me I am) just disconnected from the channel. No error message appears. Thank you for any help.