Imgur has been going through my older uploads and removing them due to TOS violations. Imgur in general has been more strict lately with questionable images containing or depicting illegal stuff on them, this is also true with their straight up ban on NSFW content recently (rip all the nsfw subreddits that used Imgur as a host)
Re-plug router to get new IP or use VPN, use incognito mode and you're good to go.