Tumblr does not have any warnings from the App Store for unknown reasons
The Community Platform Tumblr application is not a warning on App Store. Tumblr officially stated that the problem was still solved, but that reason has not been explained. Tumblr is still not visible in iOS App Store.
According to the PiunikaWeb report, many Twitter users complained that Tunblr disappeared from the App Store, causing users to download the app. The official Twitter also confirmed the news 11/16 and said it has been actively corrected.
We're working to resolve the issue with iOS, and we hope to be fully operational soon. Soon we will appreciate your patience.
– Tumblr support (@Tumblrsupport) November 16, 2018
Although the reason is not clear, but based on past experience, it may be related to the illegal content of the forum. For example, the Chinese Bullet newsletter was removed from Apple due to copyright issues in the app. The well-known communication software Telegram was also forced to unload due to child pornography.
According to The Verge, some Tumblr users send adult content to browse (including adult art photos or illegal images). In 2016, the Indonesian government imposed a temporary block on the platform and the blockade was resumed one day later. Therefore, it is suspected that the Tumblr down event may be associated with "infringement content".