Authentiucation Failed – constant messages

I changed my password on outlook.com.

X1 naturally noticed the difference because it could not login and warned me with [AUTHENTICATIONFAILED].

Fine, change the password in X1. Test the credentials. All looks good.

But X1 now keeps throwing up an [AUTHENTICATIONFAILED] invalid username or password for my @outlook.com address.

The puzzling thing is that I paused all indexing, but still that message keeps appearing.

I thought it might just be old messages popping up, so I exited X1. Messages vanished. But start up again, and they reappear. Pause all indexing, but still they happen.

I have removed Outlook.com as a data source, but still the messages keep popping up.

What gives?

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