System error, please contact your system administrator

What causes this issue?

The system came across an unknown error.
Details on the location of the error:
Program: &V1&
Location: &V2&
Function called: &V3&
Return code: &V4&

System Response

Processing was terminated.

How to fix this error?

Please note the text in the error message and contact your system
administrator.

Error message extract from SAP system. Copyright SAP SE.