Error "Unsupported response mode: auth0_pq_oid" when Launching Application through IdP-Initiated Sign-On

This article explains the following error that occurs intermittently when launching an application from the Okta dashboard using Identity Provider (IdP) initiated sign-on:

unsupported_response_mode: Unsupported response mode: auth0_pq_oid

• Okta SAML Integration
• IdP-Initiated Sign-on
• Terraform

The issue is caused by a Terraform configuration that incorrectly updates the client_protocol variable to oidc. This is not a valid entry for the protocol field and causes the system to fail during the authentication flow.

The error message may vary, depending on the invalid value included in the configuration itself. Other reported variations of the error may include: auth0_pq_oidc or auth0_pq_openid.

To resolve this issue, update the Terraform configuration to ensure the correct protocol is used.

1. Open the Terraform configuration file.
2. Locate the client_protocol variable within the configuration.
3. Update the client_protocol value from oidc to oauth2.
4. Apply the Terraform changes to update the environment.
5. In the main dashboard, verify that the Response Protocol now displays as "OpenID Connect".