No valid change request can be assigned

What causes this issue?

The system could not determine a valid Customizing request or create a
new change request failed.
The program prepares the EC-CS Customizing transport by placing the
selected objects in a transport request. (The actual transport occurs
after you release the request in the Customizing Organizer.)
This process requires a valid change request.

System Response

Nothing will be transported.

How to fix this error?

After you successfully start the transport program, specify a valid
Customizing request at the transport request prompt window.
To find an existing request that is suitable, you can display all of
the currently modifiable customizing requests in the
<DS:TRAN.SE10>Customizing Organizer</>.
Otherwise, check whether you are authorized to create customizing is
given.

Error message extract from SAP system. Copyright SAP SE.