Field &2 of provider &1 cannot be converted into transient InfoObject

What causes this issue?

Field &2 of DataStore object &1 cannot be converted into a transient
InfoObject (because of length, or type) and therefore this field cannot
currently be used in a DataStore object. This feature has not been
implemented yet.

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

Error message extract from SAP system. Copyright SAP SE.