ALE SYSFAIL error: Target\program\client &1, user &2, function &3, TID &4

What causes this issue?

This message describes the monitoring functions in the Alert Monitor.
Transactional RFC (tRFC, Remote Function Calls) is a function that
transfers data between SAP systems or between an SAP system and an
external component.
Here, you can see the log messages for calls that ended with an
exception in the destination system or destination component. These
calls are kept in the tRFC and are not repeated automatically. To remove
the error, you must solve the problem that caused the execution error.
Calls with SYSFAIL errors can be tRFC calls from ALE or tRFC calls from
other applications. You can also use the ALE monitoring tree to
investigate the ALE SYSFAIL calls. The ALE monitoring tree includes
views of the ALE queue or other entities.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Each SYSFAIL error generates a log message. The log message contains the
information you need to identify the call. You can use the analysis
method or transaction SM58 to display the SYSFAIL calls. The display
gives you more information about this problem. Note: You might not find
log messages for all calls with SYSFAIL errors. The Alert Monitor only
has a limited amount of space for these messages, which means that some
are deleted. For a complete view of all calls with SYSFAIL errors, use
the analysis method for the monitoring tree element 'Number of SYSFAIL
Errors'.
SYSFAIL errors have level red. These errors are programming or
configuration errors which require intervention before they can be
removed.
Once you have solved the problem, you can trigger the processing of the
call manually in transaction SM58 or in the analysis method for tRFC.
Otherwise, you can delete the calls in the LUW and ask the user to
repeat them. Before you delete calls, always display and print their
data, so that the user can reconstruct them.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.