Purchase Order doesn't fin approver

 Purchase order finishes with "no approver found".

I have created approval groups and assigned them positions; have created employees and assigned them positions; I have created the hierarchy, have run the Fill hierarchy Process.

However, purchase order doesn't get approved, even if the purchase order is 5 dollars. Seems that the amount rules aren't taken into account.

the PO passes throughout the hierarchy and doesn't find apporver even if the amount is little.