How To Fix VF170 - Value of open quantity must not be greater than &1.

SAP Error Message - Details

• Message type: E = Error

• Message class: VF - Billing

• Message number: 170

• Message text: Value of open quantity must not be greater than &1.

What causes this issue?

The open quantity may not exceed the comparison quantity. The comparison
quantity is figured from the difference of order or delivery quantity
and the previously-billed quantity in order and delivery reference
documents.
In billing reference documents, the comparison quantity is equal to the
billing quantity.
The amount you entered is : &V2&
The comparison quantity is : &V1&

System Response

The system rejects processing of the open quantity you entered.

How to fix this error?

Change the manually-entered open quantity to a positive value that is
less than or equal to the comparison quantity.

Error message extract from SAP system. Copyright SAP SE.