Viewpost assigns check numbers when the checks are synced from QBO to Viewpost and sent to the vendor. Unfortunately, QBO has a bug in their system that does not remove the "Print Check" action item and does not put the check number on the check detail page. There are 2 ways to correct this problem.
1. Click into the check detail and uncheck the "Print Later" box. The Viewpost assigned check number will now appear.
2. If you have more than one check to correct, click on the "Print Check" action item. Click on the box to the left for all checks sent through Viewpost. Then click on the "Remove from List" button. This will uncheck the "Print Later" box on all the checks selected and the correct check number will be on the check detail plus the "Print Check" action item will be removed.