Issue while creating Billing Document in standard Order to cash cycle

Hi Experts,

I have created a sales order a delivery and a billing  document but generally when a billing document gets saved data gets posted to accounting . In this scenario when i am creating a billing document it is giving me an error message no account is specified in item 0000001002. Kindly guide me with the issue.Sorry if i am posting it again but i am not able to solve it . i have just followed some of the Posts . As per my knowledge i  did the below mentioned things :

1. Account assignment  group maintained in customer master
2. Account assignment group maintained in Material master
3. Account keys maintained everything is maintained already since i am testing in IDES system .
4. Account assignment is coming in sales order and billing document
5. When i have gone to analysis view in the billing document it is giving me a message as G/L account 800002 determined from account determination KOFI. But when I go to VFX3 to release the billing document it is throwing me an error as " No account wasspecified for account type " S "  in item 0000001002" of the FI/CO document

Error screenshot attached

Error " No account is specified in item 0000001002 "

Kindly guide me if any of the configurations steps are missing

Regards

Parikshit