The same issue for me : Unauthenticated Request ID: NJSTIF5IZ4T2ABAJ7KAOG6W5M****

I just solved this issue. 1: Go to https://mockuphone.com 2: find iPhone 8 Plus and add your screen shots (iPhone SE 3rd gen) 3- Download the images and open with preview 4- Resize the images 1242 x 2208 . Notice to set the pricise pixels you need to unmark scale proportionally Good luck William Farhang