Windows 11 mail - imap ?

[king1]

first thing i do if you haven't already,  try and login at https://www.spark.co.nz/xtramail/signin/
This confirms that the email address and password are correct. (9 out of 10 times this is why thunderbird fails)

The mail app in Win 10 is yuck so I would just forget that...  Thunderbird is a good choice, but...

Thunderbird will for some dumb reason, always auto select POP for xtra email...

Once it has done that, go to the "manually configure" option listed (below server settings iirc) and change
pop to imap
pop.xtra.co.nz to imap.xtra.co.nz
and the incoming port to 993

everything else should be ok but confirm they match the spark settings

Then you need to "re-test"  and Thunderbird will "magically" find the right settings you gave it...

Then it should all just work...