Selected set of appropriation requests cannot be planned simultaneously

What causes this issue?

The selection criteria you entered lead to the selection of
appropriation requests that are assigned to different appropriation
request types. It is only possible to plan appropriation requests
together in the overview if their planning profiles are maintained
correctly, and if they have the same settings for currency scaling and
the number of allowed decimal places.

System Response

The selected group of appropriation requests cannot be planned
simultaneously.

How to fix this error?

Check if their planning profiles are complete, and see if these are the
same.
If it is your intention for them to have different settings for
currency scaling and number of decimal places, you should use the
appropiation request type as an additional selection criteria.

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.