So obviously this is a larger issue than just simple settings and account status and can also be a combination of these. I have a Q80T and the S20 Ultra. I've verified my TV is on the same network (wifi or lan), logged out and back in, verified privacy policies, full reset, reset the photos I had already uploaded, etc. It worked for a short time but after uploading various photos to different ambient modes something happened and it just stopped working entirely. All other modes work just fine. I tried to find a way to reset just the ambient mode feature which led me to simply reset the whole TV, which didn't work. I restarted my phone and cleared cache on the smartthings app... still nothing. Some of these tips might work but only if you're narrowed down to a specific issue but the fact remains that ambient mode itself can get locked up on custom settings regardless of any other setting on the TV with no clear way to reset it.
To be clear, I am only having this issue on the Auto Gallery Ambient Mode setting. All other "My Album" modes are working fine and allow me to upload photos. A couple more tricks you can try are to uninstall the Gallery app on the TV (I have a theory that this specific Ambient Mode uses the Gallery API to display custom photos as this trick allowed me to upload photos again to the other modes except for Auto Gallery). The other trick is to go into each My Album mode (Style and Settings) and Reset Photos.
Other than this we might just have to wait for another system update to see this working again. I tried to find a service menu but unless I'm mistaken, this isn't an option unless you have a specific remote with all the buttons necessary to enter the service menu. I'm not sure that would help anyway since I don't know what options are in the service menu but I was trying to find a way to delete the Auto Gallery mode and reinstall it.
