All Oracle Error CodesOracle DBA Forum

OCI-21500:

internal error code, arguments: [string], [string], [string], [string], [string], [string], [string], [string]
Cause: This is the generic error number for the OCI environment (client-side) internal errors. This indicates that the OCI environment has encountered an exceptional condition.
Action: Report as a bug - the first argument is the internal error number.