ExpressRoute subnet overlapping error message
I was adding multiple vnets to an express route to our local office network.
When creating a virtual network it auto creates a fixed gateway subnet of 10.1.0.0/24, and when you connect multiple of these to an express route using a virtual network gateway AND a 'connection' the fact that another virtual network gateway was overlapping is quite hidden.
Currently when creating a connection with a vnet that overlaps an already connected one, it fails with this error message:
ErrorMessage: An internal error has occurred. , DEBUG Message: Unable to connect Virtual network vn-sea-btg-prod-myfloor-arm to circuit. One or more existing connections to the ExpressRoute circuit has an address space overlapping with the virtual network being connected
Which isn't shown in the UI, it requires you to look at the json response.
What it should show:
An error that actually says the virtual network and subnet that overlaps with the currently added one.
Hopefully this one is simple enough.
(azure support ticket 120101523002652)