Instagram began reviewing new and existing apps before granting full API access starting December 3, 2015, but the changes for apps created before November 17, 2015 only went into effect on Wednesday, rendering any remaining third-party apps that implemented photo feeds virtually useless.
Third-party websites that enabled users to search Instagram photos and hashtags, such as Gramfeed and Mixagram, also ceased functioning on June 1.
"Goodbye! As of June 1st 2016, Gramfeed will no longer function. To conform with the Instagram API Platform changes, Gramfeed had to be transitioned to a new service called Picodash and is focused on providing the search and social media management functionality to brands, publishers and journalists."
Instagram's new Platform Policy is available on its developer website.