Function &1 cannot be processed because no valid resource data selected

What causes this issue?

During processing of a PP/DS planning function(s) one or more elements
have been selected to be displayed/changed, which refers to a blocked
location. In some PP/DS applications also navigation to a planning
element for display purpose may get denied, depending on the user role
assignment.
In general such elements should have been deleted within the blocking
process of a location, so that a planning situation causing this message
should not occur more often.
Here are some example situations listed, which can be given:
+,,Operation(s) assigned to a resource selected for rescheduling, fixing
or unfixing, allocation or deallocation, ...
+,,Block or Downtimes Maintenance called for a resource
+,,Order element selected for "Order Processing"
...

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?

Procedure for System Administrators

If the message occurs more often within your planning processing, inform
the resonsible person(s) for the "End of Purpose (EOP) process. More
details can be found in SAP Note: "2249093 - Simplified Blocking and
Deletion of SCM location".

Error message extract from SAP system. Copyright SAP SE.