Error during generation but dynpro was saved

What causes this issue?

It was possible to create, but not generate a screen. Syntax errors or
inconsistencies were revealed.

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?

Eliminate the screen errors using <DS:TRAN.SWUG>transaction SWUG</> and
generate the screen again.

Error message extract from SAP system. Copyright SAP SE.