US citizen here. I tried for an e-visa in January. Completed the application, uploaded my passport and a separate passport quality photo, paid the fee. The separate photo was not accepted - 'not clear'. I tried twice more with different pictures and got the 'not clear' both times. Gave up and received a VOA, so I had to essentially pay the fee twice. (I didn't want to argue at the VOA counter - it was 3 AM and there was a language barrier.) The other unclear part was that I had good information that if I was stamped into Qatar, I would not need a VOA for Oman. I was stamped into Qatar (left the airport) 24 hours earlier, but the VOA counter seemed to have no knowledge of that either. Note that QR did not inquire as to my visa status when I checked-in at IAD.