#FediBlock recommendation, there's a rogue server cloning lots of real accounts so it can impersonate them. There is no legitimate reason for such behaviour, admins should suspend it ASAP:
mastodon.arell.ai
Admins might want to suspend the main domain:
arell.ai
This would be good in case the owner tries the same stunt on a different subdomain. Blocking the main domain also blocks all of its subdomains.
(via @thomas, thread at https://metalhead.club/@thomas/114878505580336321 )