I think that's what it says but that's the error I'd say I get about 40% of the time when trying to view image posts. Is this a sync thing or something else?
I have no idea why, but I just tried it again and it loaded for me this time. But it wasn't loading and I got the exact message described in the original post at the time.
Kiwi here, no such issues with my Sync. Is there a particular community where you see these errors mainly (if so, can you link it here)?
Also, when you get those errors, it might be worth accessing that community directly using a local account - and if the images load fine, that would point to a federation issue with your server.
For me it's because for whatever reason, Verizon has files.catbox.moe DNS blocked so any picture using that service to host fails to load when using phone data. Your problem might be something similar.
@boogetyboo there's still a good chance you're using your Internet Service Provider's DNS.
Not only does this mean its super trivial for them to block things they don't want you to access, but this also means they can see (and they probably log) everything you do; no good for privacy or freely accessible info
Try switching to something like quad9, and reboot your devices after to make sure they've cleared their DNS cache
PS:
You can just add dns.quad9.net to Settings > Network > Private DNS on Android if you don't want the app.