Hi Ludwig,
Thanks for your reply.
Yes, I am trying to post the payment journal for the Step 1 and Step 3. When tried to Settle both Step 1 and Step 3 at a time system won't allow to post. But when tried to settle only Step 1 system allows to post. But not for the Step 3.
Let me explain the steps I followed.
1. Created a Time and material project and assigned a Project contract (No billing rule defined).
2. Requested for a Customer Advance payment.

3. Posted the Invoice proposal for the above advance payment.

In on-account transactions form, we can see 2 Transaction types created after posting the Customer advance payment.
A. Transaction origin: Prepayment journal voucher, Invoice status is fully invoiced. (Customer balance has increased, but not posting the payment journal as of now and continuing to post the Expense,Fee,Hour Journal ).
B. Transaction origin: Deduction, Invoice status is Chargeable.
4. Posted Hour, Expense and Fee Journal.

5. Now executing the Invoice proposal.

In the above snapshot it sows all the expense transaction types.

In the above snapshot it shows the deductions, (Please note: I have not posted the payment journal for this amount)
So, Below is the Invoice proposal screen for which I am Posting the invoice and recognizing the revenue.


Below are the posted Transactions and its Invoiced Status:-

Now I am trying to post the Customer payment Journal and settling both the Invoice open:
Below are the Two open Invoice One is for the Customer Advance payment of 10,000$ and other is the Expense total 427,000$ :

While Posting Below is the Error "Operation canceled: Validating and Posting Journal" and eventually it Locks the Journal batch.


Now, I am trying to Unlock and select only the Customer Advance payment of 10,000$.

Here system allows to post the transaction without any error.

Now I am trying to Post the payment journal for the other Invoice 427,000$


Here is the Problem, I am unable to post the payment journal for this Invoice.
Am I missing something here.
Regards,
Sandesh