I've seen this error twice now, and had not encountered it while creating previous bots. When I Google the exact error message (spaces or not), I receive no results (Shouldn't there be some MSFT documentation out there?)

The Error, as I see it on the screen, looks like:

AuthenticationInputNotEnabled
"Authentication Input Not Enabled" has not turned up any results in this forum either (perhaps until after this post is published).
In the main Settings->Security page, I go into the Authentication screen:

I have Only for Teams and Power Apps enabled.

Under Generative AI, I have two Sharepoint Sites listed:

What am I not seeing?