The following workaround should get you into the game and back to enjoying all of its features:

  1. If it is open, close Terraria completely
  2. Turn on your phone's Airplane Mode so that no data or wi-fi is enabled
  3. Start Terraria (you will likely still get the same error message, but the game should load to the main menu now)
  4. Once you're at the main menu/title screen, turn Airplane Mode off
  5. Now you can login, access your cloud saves, and get back online