Changes to repository or cross-client customizing are not permitted

What causes this issue?

In this logon client, any changes to the Repository and to cross-client
Customizing objects are prohibited.

System Response

The function terminates

How to fix this error?

If you still want to make the changes, contact the system
administrator, who can allocate you a user in a client where you can
make the changes.

Error message extract from SAP system. Copyright SAP SE.