In case you missed it...
Mastodon.social and mstdn.social are totally different servers.
They are owned and run by totally different people.
Mastodon.social is owned by @Gargron
Mstdn.social is owned by @stux
They just have similar-looking names, that's all.
@mtomczak @feditips @Gargron @stux Gonna register mASStodon.social