To summarize the setup please see a basic outline of how the routing works:
In a nutshell, we use Azure to host some IaaS as-well as use the Azure backbone as a sort of WAN to connect our corporate network, and a remote site. This is achieved with routing tables and a VNA.
However the Azure routing seems to have failed on me, as I can no longer reach 10.21.0.0/22 from the Corp network. The packets are being routed as per the snippet of the routing table in the above image, but they are not hitting the VNA on 10.101.49.4 (confirmed with packet captures).
From the VNA on 10.101.49.4 I can reach all addresses within the Corp network, and all addresses within the remote site (10.21.0.0/22).
This has suddenly stopped working twice now, with no changes at all within our environment.
Please, any assistance is much appreciated!