Hi Dhamodharan,
Open Payment Journal form and right click “Name” > Go To Main Table. It will take you to the Journal name Form. Check for “Active” checkbox and “Approve” field for the same journal name.
If checkbox is checked and Approve has an user, then only that user is allowed to post the journal. So, Either clear off Active checkbox or get the same permission in order to post the journal.
Hope it helps.
Monika.