The dynpro name & & is invalid

What causes this issue?

Your screen specifications are invalid. You have either not specified
the program name or screen number, or the screen number does not lie
between 0001 and 9999.

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?

Enter valid screen specifications.

Error message extract from SAP system. Copyright SAP SE.