Invitation send. I haven't had a chance to test using http as opposed to https but I have forwarded the http port which was previously closed. I may be worth mentioning that I was not connecting through Emby Connect but directly to the server on the https port.
Okay, I can connect fine and I am able to access settings fine but I am able to reproduce the flashing images problem.
This tells me it must be related to either the server or the images/data in question because I have never seen this on my device before. The app isn't throwing any errors or even logging anything so whatever is going on is at a lower level.
I tried disabling backdrops but that didn't have any impact. Once the images start flashing, you can arrest it by navigating to another row - temporarily. Once you then move somewhere that will cause more images to have to be loaded, you get the flashing again. It looks like the images are being loaded over and over again.
Can I please see your server log from the last 30 minutes or so?