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?