Not able to post invoices to Accounts because of the error “Posting Period xxx 20xx is NOT Open”
Solution : This problem needs to be corrected from the FICO configuration end. Anybody who has taken SAP FICO Training would be able to fix this. The transaction code to fix this is [ OB52 ]
Select the account type, fiscal year variant and change the “To Period” to the current year, period. That’s it – you are done. Now, save it and go back to the invoice again and release it to accounting.

I am learning MM module and was getting similar error messages when I was trying to do MIGO. I just followed that 3 steps that you showed, OMG I was able to do the posting. Honestly, I didnot understand what I did, but still mighty impressed by the small post. In the middle of the night I could not have asked for more. Thanks…
Mansoor
Hello Siva Sir,
I am getting this message when i am trying to create an order for Delivery;
Posting only possible in periods 2009/07 and 2009/06 in Company code 3000.