APPROVAL REQUEST INVALID

Hello everyone,

I set up approval process for quality. I have two approver group for first approve and second approve. I can enter and change tests in P3701, P3702 and P40318, however P3702 is a problem. I can enter and approve test in P3702, but i cannot change. When i change a specification in P3702, first approver can approve the specification, an it comes to second approver's view. However, when second approver try to approve it gives error as "approval request invalid".

NOTE: The system let  the second approver to cancel, but doesnt let approve.

Thanks