LU-LU session initiation fails

Problem statement: A severe error that prevents session initiation has occurred.
Common symptoms: Message IST663I is issued and contains a sense code describing the reason for the session initiation failure.
Probable cause: The RTP connection manager (RCM) experienced a severe error.
User response: Determine which node in the session path has experienced the error; obtain a VTAM® dump, including a VTAM internal trace (VIT) with the HPR options.