Outlook 2019 & Xtramail

[king1]

Correct me if I am wrong:

I can leave my xtramail account in my Outlook but of course, it can't access the Spark's xtramail server.
But, will Outlook 2019 spit out any error message other than access failure or something to that effect?

Being POP, yes you can do it that way.

To stop Outlook from giving those access failures (the username password prompt) every 10 minutes or so then you need to remove the pop account from the mail settings.  The data file itself should stay in place but back it up anyway just in case, it is stored in documents / outlook files usually... Outlook would need to be closed to copy it...

This is the area you would do that 
https://filestore.community.support.micr...1e94c13bc1

File -> Account settings -> Account settings