Ensure the Cognos service account has sufficient permissions to access the database and the local temp folders used by the query engine.
: In some environments, like IBM OpenPages , using a non-English locale setting can cause connection failures with this error code. Ensure the Cognos service account has sufficient permissions
Firewall, security groups, and network ACLs like IBM OpenPages
A typo in the connection string is a frequent cause of the xqe-jdb-0001 error. Go to your Data Source properties in Cognos (or your specific application) and check the connection string. Ensure the Cognos service account has sufficient permissions