Description
If Schema Type is set to Input schema must match target schema, schemas of input feature classes must match the schema of the target feature class.
Solution
Ensure that the input feature classes or tables have the same attribute schema as the target feature class. If the schemas are not the same, you can set the Schema Type parameter to Use the Field Map to reconcile schema differences, so only those fields and their values in the input that match fields in the target dataset are used. See the Append tool documentation for more information.