Cannot connect anymore to my VN

HI All,

I have a 2 VM 2012 servers on azure, one is DC , one is a remote app server,
Have on VN configured,

details here:

<NetworkConfiguration xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/ServiceHosting/2011/07/NetworkConfiguration">
  <VirtualNetworkConfiguration>
    <Dns />
    <VirtualNetworkSites>
      <VirtualNetworkSite name="OTAP" AffinityGroup="BISID-VNET">
        <AddressSpace>
          <AddressPrefix>172.16.100.0/22</AddressPrefix>
        </AddressSpace>
        <Subnets>
          <Subnet name="Development">
            <AddressPrefix>172.16.100.0/27</AddressPrefix>
          </Subnet>
          <Subnet name="Test">
            <AddressPrefix>172.16.101.0/24</AddressPrefix>
          </Subnet>
          <Subnet name="QA">
            <AddressPrefix>172.16.102.0/24</AddressPrefix>
          </Subnet>
          <Subnet name="Prod">
            <AddressPrefix>172.16.103.0/24</AddressPrefix>
          </Subnet>
          <Subnet name="GatewaySubnet">
            <AddressPrefix>172.16.100.32/29</AddressPrefix>
          </Subnet>
        </Subnets>
        <Gateway>
          <VPNClientAddressPool>
            <AddressPrefix>172.16.99.0/24</AddressPrefix>
          </VPNClientAddressPool>
          <ConnectionsToLocalNetwork />
        </Gateway>
      </VirtualNetworkSite>
    </VirtualNetworkSites>
  </VirtualNetworkConfiguration>
</NetworkConfiguration>

There is a certificate in place. But i cannot connect to the VN using the VPN Client

Am getting a certificate error :  (0x800b0109).

I have no idea how to fix this

Regards

hans