Program error occurred

What causes this issue?

A program error occurred. This should not occur in normal system
constellations.

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?

Contact an expert who can analyze the error in debugging. If this
provides an explanation of the error, contact the SAP Hotline.

Error message extract from SAP system. Copyright SAP SE.