...
The client secret for you OIDC integration is expired.
You accidentally copy/pasted in the wrong value. E.g. Microsoft Entra ID /Azure AD offers a secret ID field which is often confused with the client secret itself
SAML
Why do I get the error code SUBJECT_CONFIRMATION_DATA_UNEXPECTED_IN_RESPONSE_TO?
When a user is redirected from an Atlassian Data Center instance to the identity provider for authentication, the redirect includes a unique authentication request ID. When the IDP later returns the user to the Atlassian Data Center, the SAML Response from the IDP must contain an inResponseTo attribute with the same ID. If the addon receives a SAML Response with an unknown responseTo ID, you will see that error message.
...