A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider. (Error 0x800b0109)

Hello there all

We've been successfully connecting to our Azure VNET via a standard point-to-site VPN configuration for more than a year. We originally created individual certificates for each user, as described at:

https://azure.microsoft.com/en-gb/documentation/articles/vpn-gateway-point-to-site-create/

...And they have worked just fine for a year or so.

Now, halfway through our morning, we suddenly can't connect to the VNET. Earlier in the morning, we connected successfully.

We now get the error:

A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider. (Error 0x800b0109)

Any ideas? Thanks a lot.