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Login to Cognos Analytics with Azure AD / Entra OIDC namespace fails due to request query string being too long. How to diagnose and resolve.

Troubleshooting


Problem

Users are unable to log on to IBM Cognos Analytics when using Azure AD / Entra ID OIDC namespaces in conjunction with IIS web servers. The authentication request fails because the query string length of the OIDC completeAuth.jsp callback URL exceeds the maximum values configured in IIS.

This behavior began appearing in some environments in January 2026, despite no changes being made to Cognos Analytics.

Symptom

Depending on the topology and how IIS is fronting Cognos Analytics, users may encounter one of the following symptoms when logging in:

1. HTTP 404 Not Found

A browser-displayed 404 error returned by IIS for the URL:

/ibmcognos/bi/completeAuth.jsp?code=....&state=....&session_state=....

2. Cognos Login Authentication Error

A pop‑up message in the Cognos Analytics UI:

CA Login Authentication Error
Cannot login

This also occurs during the request to:

/ibmcognos/bi/completeAuth.jsp?code=....&state=....&session_state=....

Document Location

Worldwide

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Document Information

Modified date:
21 January 2026

UID

ibm17257700

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