I've created a simple webapplication running on an azure virtual machine. The application is also displaying data from another website (http, 80), hosted outside of the azure cloud but also under my control.
This worked now for about a year and suddenly stopped: I only see a timeout while the azure-hosted webapp is trying to connect to the other website.
1) The website outside of azure is online and reachable from any other machine I tried
2) The website outside of azure is NOT reachable in a browser within the azureVM: I only get a "ERR_CONNECTION_TIMED_OUT", a simple timeout
3) Other common websites are reachable from the azureVM
4) Firewall deactivated, still doesn't work
5) NSlookup from the azureVM to the domain outside WORKS and delivers the correct IP
I'm a bit puzzled, but maybe someone here knows what this might be and how I can fix it.