I had to reset Process instance to 0 (Step 4) to resolve the issue.
The usual causes are due to some form of non-selection criteria or prior data corruption.
Summary Checklist: If any of these conditions is met (answer is Yes), then the group should post. If any is not met, the group will not be selected or if selected will not be posted.
1. Group Post Action is Set to Post Now or Post Later?
GROUP_CONTROL.POST_ACTION <> 'N' or 'L'
2. Group Accounting Date within Run Control Date Parameters?
PS_POSTING_REQUEST.POST_FR_DT and POST_TO_DT
Check date including century (e.g. 20-Feb-06 may mean year 0006 or 2006)
3. Group Post Status is NOT Set to 'Complete'?
GROUP_CONTROL.POST_STATUS <> 'C' means group already posted.
4. Customers, Items or Groups Process Instance = 0?
CUST_DATA, ITEM, GROUP_CONTROL, PENDING_ITEM, DEPOSIT_CONTROL, PAYMENT, (Maintenance Worksheet) WS_CONTROL: PROCESS_INSTANCE = 0?
If the PROCESS_INSTANCE <> 0 then the record(s) are still locked by a prior process.
5. Group or Pending Item Accounting Dates in Open Period?
FIN_OPEN_PERIOD table. If period is closed, the group if selected will return an error code of 'C' (Closed Period).
6. PS_RP_PARALLEL does NOT contain records of groups?
If the group_Id is left-over in PS_RP_PARALLEL, it will not be selected in the next Receivable Update run. This table is used by running processes only and should ideally be empty once a processs is completed successfully.
7. Origin IDs PS_AR/PS_BI and Group ORIGIN_ID defined AND Group ORIGIN_ID Effective Date is earlier or equal to Group Accounting Date (e.g. Origin PS_AR 01-Jan-2005 Group 01-Feb-2005)?
8. Bill-To-Customer Effective Date earlier or equal to Pending Item effective date?
9. Setup > Install > Options > Receivables 'No Mult Pending Item Selection' is checked and Item or Pending Item is New?
Check if the process used the same item number as a previously posted item.
10. The Payment Terms setup has correct Timing ID defined?
PAY_TRMS_TBL, PAY_TRMS_NET & PAY_TRMS_TIME.
Check the payment terms. Verify that Timing ID was set up, such as payment terms equal NET30, and a timing ID set up for 30. You must define payment terms timing IDs before you set up payment terms. To define payment terms and payment terms timing IDs, use the following pages: Payment Terms. Payment Terms Timing.
The trace file step AR_POSTING.TRM_DEFN.GET_DEFN would show 0 items if there is a setup issue.. This step refers to Payment Terms and their timing. The tables are: PS_RP_TRMBAS_TAO4, PS_PAY_TRMS_NET, PS_PAY_TRMS_TIME.
11. Item Payment Method is populated (Not Blank)?
PS_ITEM.PAYMENT_METHOD If blank, the payment referencing that item will not be posted.
12. PENDING_ITEM.DST_ID_AR is populated (not blank)?
If this field is blank and the group selected, you will receive an ACTOB (accounting entries out of balance) error.
13. ARUPDATE Generates Error 'Group (BUnnn,ID) to be Generated Already Exists. Group Type='?' and a group is not posted?
Check Document ID 620227.1 for more detailed analysis.
If all the above seem OK (all answers = Yes), then try:
Receivable Update with a NEW Run Control parameters (the current may be corrupted)
These are the tables you will need to check:
PS_PENDING_VAT (only if VAT is relevant to BU)
PS_CUST_OPTION where CustID = 'xxxxx'
PS_CUST_DATA where CustID = 'xxxxx'
PS_SUBCUST_DATA where CustID = 'xxxxx'
PS_ITEM where Item = 'xxxxx'
PS_ITEM_ACTIVITY where Item = 'xxxxx'
PS_ITEM_DST where Item = 'xxxxx'
PS_ITEM_ACT_VAT where Item = 'xxxxx'