Informix Error -950: User username is not known on the database server.

Reasons / Common Causes

-950 fires when a statement references a database on another computer system, but that remote server doesn't recognize the connecting account — per the official guidance, a valid trusted login identity is required on every database server accessed remotely; this message specifically appears on PAM-enabled servers.

1. No trusted login identity for this account on the remote server, per the official guidance — the direct, only cause.
2. PAM (Pluggable Authentication Modules) configured on the remote server, per the official guidance's specific note, with the connecting account not recognized under that authentication mechanism.

Solutions / Resolution

1. Ask the database administrator to put your login ID in sysuser:sysauth on the remote server, per the official guidance — this is the documented, specific resolution.
2. Confirm whether the remote server has PAM enabled, per the official guidance's note, since that's specifically when this message appears — the underlying account-recognition requirement is the same either way.

Examples

N/A

A remote-server account-authorization problem — escalate to the DBA for that specific server, per the official guidance's sysuser:sysauth pointer.

Diagnostic Checks

1. Identify the specific remote server named in the failing statement.
2. Escalate to that server's DBA to add the account to sysuser:sysauth there.

Related Errors / Related Topics

• -763 — "Error in auditing environment initialization." A related security-configuration error, about secure-server connection problems more generally, escalated similarly to the security administrator/DBA.

Escalate to the remote server's DBA to add the account to sysuser:sysauth there — this is a remote-side authorization gap, not a local configuration issue.