I am planning to use Azure Traffic manager to do a failover of my app running on one Azure zone to Azure zone. I need some suggestion, if that is the correct approach to do a failover ? We have seen issue with Azure that, most of the services in one region goes down for few hours. Although I understand that Azure traffic manager is not associated with the region. But is it possible that Azure traffic manager goes down or that traffic manager endpoint is not reachable although my backend webapp is reachable?
If I am planning to use Azure traffic manager, what are other problems I should be worried about ?
Traffic Manager works at the DNS level, which itself is replicated. However, even then, you should still build in redundancy into your solution.
Take a look at the Azure Architecture Center under "Make all things redundant" and you will see a recommendation for Traffic Manager:
consider adding another traffic management solution as a failback. If the Azure Traffic Manager service fails, change your CNAME records in DNS to point to the other traffic management service.