Looks a bit to me that you're using TOR on the phone. I have not checked if Lemm.ee is using cloudflare or a form of CDN to fetch the thumbnails. If some malicious actor is exiting from the same exit node as yourself, its likely that the CDN have temporary blocked the IP address by the CDN being provoked.
To resolve that, refresh the onion relay by clicking 'New Circuit' within the menu or simply close the TOR browser completely (and background tasks), before navigating to the website again to get a new exit node.
Edit: I failed to see you seem to be using chrome in the picture. My bad ^^ Happy new Year Though!
Since Pavel Durov; the CEO of Telegram got arrested, I just instinctly have avoided telegram all together. I actually stopped two years before he got arrested as I just simply felt uneasy with the app. No encryption by default. Using obfuscation rather than encryption. But that's just my opinion. Jumped over to signal and feeling much happier