Unable to find or follow other accounts (Pixelfed, Fedified WordPress...)

Just created my pod and installed Mastopod.
- was able to follow and be followed by my main Mastodon account.
But:
- **Pixelfed**: account is found, appears on screen, but the follow button seems to do nothing.
- **Friendica**: blank/empty Mastopod screen
- **WordPress** + ActivityPub plugin (x 2): blank/empty Mastopod screen

No files or tests are named in the issue. Reproduce it by running Mastopod and searching/following Pixelfed, Friendica, and WordPress (ActivityPub) accounts, then trigger the follow action. Next, trace the remote account lookup and follow-request flow plus the path that renders empty/blank account results. Done means those external account actions work and no empty screen appears for the tested providers.

Escrita pelo modelo de indexação a partir do texto da issue.