Concurrent request Error: The executable file for this concurrent program cannot be executed.

Issue: Concurrent request completed with below Error.

This request finished with an error and produced the following completion message: The executable file /$CUSTOM_TOP/bin/MAIL_SCRIPT for this concurrent program cannot be executed.

ERROR:
The executable file /$CUSTOM_TOP/bin/MAIL_SCRIPT for this concurrent program cannot be executed.Contact your system administrator or support representative.

Cause:Verify that the execution path to the executable file

Run the below command
$cd /$CUSTOM_TOP/bin
$ls -ll 
OR
$ls -lrt /$CUSTOM_TOP/bin/MAIL_SCRIPT

Output of the above command shows executable is pointing to a wrong symbolic link or not showing link.

Solution:

1.Create a soft link with the program name as below:
$cd /$CUSTOM_TOP/bin
$ln -s -f $FND_TOP/bin/fndcpesr MAIL_SCRIPT
2. Re-run the concurrent program and test the issue.