Cannot print from IOS device to an HP t650 large format printer using the HP smart app.

why cant i print from My IOS devices to my large format printer HP Designjet T650 using the hp smart app?? it gives me a message that says "your job has been sent, waiting for printer confirmation" and thats all the farther you get, it never prints. i called HP and they said that theres no hard drive in the printer, that the confirmation has to come from the ios device... so could this be a setting somewhere?? the only way i can print from ios is if i do not use the hp app and just use air print and print in 8.5x11 size. in order to print large format you have to go through the app but it wont let me.. HP says that i should be able to print large format from my ios device.. please help..