DUO 2FA not working After Update

Hi All, Cross posting this here as well as bitwarden ticket.

After updating our Self hosted Bitwarden deployment when trying to launch the page for DUO MFA we are now getting a black screen with:

{“error”: “invalid_grant”, “error_description”: “Invalid redirect URI ‘’.”}

Have tried removing the Duo setup via Recovery codes then removing the Application from the duo portal and setting up from scratch. but same issue. It seems that redirect URL needs to be changed, but how and to what?