I am getting the below error, when i am trying to insert a record from custom object into standard opportunityLineItemSchedule object by firing a trigger

Exception Mesage:Insert failed. First exception on row 0; first error: FIELD_INTEGRITY_EXCEPTION, field integrity exception: Type, Quantity, unknown (invalid quantity/revenue for given type): [Type, Quantity, unknown]

I am getting the below error, when i am trying to insert a record from custom object into standard opportunityLineItemSchedule object by firing a trigger

Exception Mesage:Insert failed. First exception on row 0; first error: FIELD_INTEGRITY_EXCEPTION, field integrity exception: Type, Quantity, unknown (invalid quantity/revenue for given type): [Type, Quantity, unknown]