We have a two VNETs setup in two separate regions. Each region has a site-to-site VPN setup between them and each region has a site-to-site to our company network (creating a triangle).
Connectivity seem stable between the two VNETs and one of the connections to the company network is very robust, however the second is experiencing intermittent connectivity issues, dropping once in a while, then recovering within minutes. During the outages, we are able to connect to the other region and then successfully hop across to the second region (proving the services are all up and running), however, we are not able to connect directly.
Our communications company have looked into this and say that then don't see the connection going down, just that during the outages they are sending data, but get no response. From the web interface, we also don't see any issues with the connection.
Can anyone advise how to trouble shoot this further?
With thanks,
Richard