Recently unable to "/join #cygwin-developers"

[Mark Geisert]

Hi folks,
At some point after the recent shenanigans on #cygwin-developers I was 
disconnected.  After a /connect to libera.chat, on trying to /join again 
I get the message:

#cygwin-developers: Cannot join channel (+r) - you need to be logged 
into your NickServ account

My mode is Ziw and I don't grok IRC beyond running /help commands :-). 
That hasn't helped.  How can I rejoin?  What is a NickServ account?
Cluelessly,

..mark