Azure Web Apps Gallery now supported only in Azure Marketplace
The Azure App Service team has been building new features in the Azure portal, and making improvements so more customers can use the community-driven Azure Marketplace. Because of this, we’re discontinuing support of gallery application creation like WordPress, Drupal, and Umbraco in the Azure classic portal. Customers can create these applications in the Azure portal and take advantage of all the available new features there.
For more information, please visit the Azure blog.