An XCOM file transfer from a remote system failed with a B37 ABEND. Our XCOM tried to send the session partner back the XCOM0221E DATASET OUT OF SPACE message, but the VTAM SEND failed with XCOMM0186E XCOM00 RC 0C FDBK2 0B SENSE 0000 0000 RECEIVE, which indicated that the session was terminated. On the session partner side, they received an XCOMM0186E XCOM RC 0C FDBK2 0D SENSE 0000 0000 SEND which was followed by message XCOMM0151I XCOM SESSION ENDED. The fact that the session partner never saw the XCOM0221E DATASET OUT OF SPACE message caused delays in their analyzing the problem.
The severity of the RC 0C tells us that the session is no longer found and XCOM will terminate processing, hence why the FMH7 and the XCOM0221E DATASET OUT OF SPACE is never sent to the sending system. XCOM relies on the RC and Sense codes to signal if it will receive something back.
XCOM r12 for z/OS, VTAM
A closer look at the network configuration would have to done in this case and it would require the VTAM person to get involved.