Anturis dashboard inaccessible; some monitors simply cannot be reached?

gumbuya 9 years ago updated 9 years ago 8
This afternoon some of our Microsoft Azure cloud services had their virtual servers re-imaged. Which is fine, since everything is back to normal operations. However, Anturis HTTP monitors from various global locations (Berlin, Vancouver, California) cannot seem to sense their availability and still report them down. No matter how I reconfigure the monitors.

After some hours, the entire anturis.com dashboard came crashing to a error 502 and cannot be accessed now.
Dashboard is back available this morning. However it looks like the monitors that alerted "offline" over the weekend still are not able to sense the recovery of the services they are monitoring.

I was dreaming; the USA location is Dallas not California.
To be more specific, the error reported on the dashboard is

Network Error
Error code: 1201
The target host is down or unreachable, refused the connection or closed the connection unexpectedly. Check if the target host is up and reachable, and the web server responds on the specified port.

Which is somewhat puzzling as we can access them without observing any problems. What is not clear is if all global monitoring agents face the same problem or only one/some of them; the graph UI only draws one line at this point of time.
Looks like if the faulty monitors are deleted off and re-created, then they can get proper HTTP responses and report the real situation. Which suggests something is wrong with the existing monitors; they are not able to report the recovered state of the services, or their monitoring mechanism has failed to detect the recovered states.

I have kept some old monitors deliberately in that stuck state.
Under review

As I see all faulty monitor are HTTPs. Looks like you turn SSLv3  off on January, 24 and after this it failed. It is old monitors and it was created before we start supporting other options expect sslv3. That is why newly created monitors returns ok. Unfortunately, you need to recreate this monitors.

Thanks for the explanation.
For additional context, Microsoft discontinued support for SSL v3 in their newly rolled-out guest OS version for Azure cloud services. It makes sense that those that dynamically update to the new version face this problem while others with fixed (older) guest OS version do not.