Test transport &1 not yet imported in &2 -> wait for import

What causes this issue?

The correction proposal cannot be set to status <LS>Tested OK</> yet.

System Response

The action was terminated.

How to fix this error?

Wait until the transport into the test system occurs. you can then test
the changes. As long as the import has not occurred, the status cannot
be changed.
For more details on the correction workflow, read the relevant Horizon
documentation.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.