That sounds like "flood". I thought most networks have a limit of 15-25 channels.

How do you join the channels, with the Feature in the Network/Server list?

Without Auth you are able to autojoin 75 channels?

It could be that you change your hostname and the server let you rejoin all channels at once, when you auth



So gives us more details, when you are disconnected and what error message you get, what happens before the disconnect, what while disconnect.