I've never seen this message but perhaps others have - OperServ is unique to the network that runs it, it has nothing to do with mIRC itself. For it to be sorted, you should wait 12-24 hours to see if it expires, and then contact an IRC Operator online. If it doesn't expire, you need to check out the network's website and see if you can find a contact email to speak to someone who knows about it.
To reiterate, this is not an mIRC message or error, and mIRC has nothing to do with OperServ disconnecting you - you'll need to speak to the network administration.
G'luck!
Regards,
