Imgur blocks access to most VPN IP addresses so any posts using the host will result in many users being unable to see the content. Sometimes only remote viewing is affected but is also often blocked when trying to open in new tab and view at the parent site.
Consider uploading to the fediverse or using a privacy-respecting hosting service like postimages.
It’s by design, to incite people to spend time on the imgur website/app with ads instead of just using for image hosting. It used to be a nerd-friendly image hosting for redditors at the beginning, but about 3 years ago they decided it’s time to try to look more respectful to make some more money out of it. They banned NSFW (and probably whatever else their investors/advertisers/payment processors don’t want to see) and automatically deleting images uploaded anonymously and not accessed enough. Interestingly, similar timing as the Reddit API debacle which created a big wave of new comers to Lemmy, including myself.
They are not a reliable image hosting service anymore, by design. https://help.imgur.com/hc/en-us/articles/26479362527771-Imgur-Terms-of-Service-Update