If a corporation, partnership, or tax-exempt organization’s e-filed Form 7004 or 8868 is rejected, can they submit the extension by paper?

Yes, paper filing Form 7004 or 8868 is allowed if your e-filed extension is rejected. However, before switching to paper, you can try to correct and retransmit the return electronically. 

With ExpressExtension, you can fix the errors and retransmit the return easily at no additional cost.