Layout &1 does not exist

What causes this issue?

The system could not find the layout you selected. Therefore, no
template could be opened.

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?

First of all save the layout concerned and then open the template.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.