The best place to check for a reject reason is in the software.
For Desktop, you will want to ensure you have the most up-to-date acks. Get-Module Updates and Acks. Then you can do a Ctrl-Q or F7 and see the status of your return.
For Online - Click Return Status - This will prompt you to enter the social security number, the year and click Search.
From there, you can select the federal or state return:
Then you can click the links on the left for rejection:
After you have figured out the reject reason, you can fix and resend the return.