mwoauth.errors.OAuthException: oauth_callback must be set, and must be set to "oob" (case-sensitive), or the configured callback must be a prefix of the supplied callback.

[rovitotv]

Greetings,
I have a new mediawiki running 1.35 and I am trying to get oauth to work with my Python Flask app. The media wiki is using the host name of https://wiki.whatever.com and the Python Flask app will use https://files.whatever.com. I have nginx in front taking care of the reverse SSL proxy. I got the example request-oathlib.py to work, at least the identity part. But I can't get the example flask app to work. No matter how I configure the media wiki oauth consumer I always get the error:
mwoauth.errors.OAuthException: oauth_callback must be set, and must be set to "oob" (case-sensitive), or the configured callback must be a prefix of the supplied callback.

I have tried just about every combination I can think of on the media wiki oauth consumer with no joy. Can somebody explain where the callback should be either https://wiki.whatever.com or https://files.whatever.com? Thank you so much for the help!