Description
The input layer and append layer must have matching fields to append by default. Fields are a match if they have the same name and type.
Solution
If appending matching fields only, verify that the input layer and append layer have fields of the same name and type.
Append fields with different names using the Append Fields parameter. The Input Field property must have the same type as the Append Field property.
Use the Append Expressions parameter to calculate field values with Arcade expressions. Verify that the Expression results have the same type as the Input Field type.