
madhubalajim.86857 (Customer) asked a question.
After authenticating, user is seeing the 400 Error with the below error. Same setup was working fine for the same user with the same setup.
Error: The 'redirect_uri' parameter must be a Login redirect URI in the client app settings: https://dev-xxxxx-admin.okta.com/admin/app/oidc_client/instance/0oa87jhxxxxoGrOc5d7*tab-general

I can't comment about why it suddenly would stop working, but the error is pretty clear - "The 'redirect_uri' parameter must be a Login redirect URI" and so it is missing in the application redirect URI section.
Couple other ideas -
1) Use Chrome's DevTools (Network tab) to investigate web session traffic from the browser while testing and see what the redirect_uri is during the non-working scenario.
2) Add both "clear text" URL along with the URL encoded value in the redirect URI section.
-Jani