0x0015000F (1376271) The System Log Stream (SLS) interface encountered an error while it was disconnecting from a log stream.

Explanation
An attempt to disconnect from a z/OS system log stream failed.

The data values identify the return and reason code values from the IXGCONN REQUEST=DISCONNECT 
request that reported the error.

User response

Review the topic, "IXGCONN — Connect/disconnect to log stream" in the “MVS Programming: Authorized Assembler Services 
Reference” in the z/OS documentation in IBM Knowledge Center for an explanation of these codes.