Your Fedi account is probably run by a volunteer on a server with no Service Level Agreement. Downtime happens! Failures happen.
You should plan for outages by having another account on a server operated by someone else. Even if it’s just the mastodon.social account that you first signed up for. You can leave it dormant and redirected until disaster strikes.
You can cross-verify your two (or more) Mastodon accounts by putting the URL of one account into the four metadata fields of the other account. Don’t forget the https:// prefix!