Read error for function selection for &1 to &2

What causes this issue?

An error occurred while a function entry was being accessed.
In some circumstances the function entry is deleted from the database
during processing by another program. If this cause is excluded then it
is possibly a program error.

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?

If the function entry was deleted check whether a new one must be
created.
If there is a program error inform your system administrator.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.