Without warning, the MAL API went down due to a security vulnerability. While our programs don’t exactly use it, we only use the account verification. This means that you may not be able to use our apps. Note that we cannot fix this issue since MyAnimeList can only fix this.
Since this issue is primarily related to DeNA (MAL’s parent company) rather than the MAL staff, sending complaints to DeNA’s customer support seems to be our best bet at the moment. If they don’t fix it, I advise you to switch to Kitsu or AniList and boycott MyAnimeList to give them a message that this is unacceptable. Note that you can easily import your lists into these sites.
However, Hachidori (excluding MAL Sync) and Shukofukurou (Kitsu and AniList services only) are not affected by this. We will report back when there are updates.
To ease the pain, I suggest using a different Anime List management service like Kitsu. If you have purchased a donation license for MAL Updater OS X, you can request a free Hachidori license by sending your FastSpring order invoice to email@example.com. We are currently working on supporting AniList soon. With that, I apologize for the inconvenience as this is out of my control. For the time being, MAL Updater OS X donation licenses are temporarily pulled from sale until I can find a workaround.