Steps to reproduce
Error logs indicating that the subscription for an IIS instance has been removed from Azure. Might happen when a site is restarted/recycled and if the new appdomain coming up is overlapping the old appdomain that is going down it be be so that the appdomain going down removes the subscription for the appdomain coming up. There is no known way to reproduce this issue.
Simulate by:
1. Setup a site running in Azure as described in SDK
2. Go into the azure portal and select servicebus
3. Find the topic that is used by the site
4. Click on the subscriptions for the topic and remove the subscription
5. Download the publish settings file for the azure web site
6. Connect to it using the FTP settings in the settings file.
7. Notice that the log file in App_Data contains a lot of entries and just keeps growing:
ERROR EPiServer.Azure.Events.AzureEventProvider: Failed to receive message
40400: Endpoint not found.
After the fix the site is able to recover from the situation. When it happens you will see 1 log message saying "Lost subscription client, recreating client to establish a new connection" but the provider automatically recovers and recreates the client instantly.
