Import "Always On VPN" Certificate does not Upload, RT-AC86U AsusWRT Firmware 3.0.0.4.386_51925

[GAndreone]

Hello Everyone,
This is my first time posting after searching this site and other sources.

The RT-AC86U is being used as an edge device on a Windows Server 2019 Essentials. The WinServer is in the process of being setup as an "Always on VPN IKEv2"
This setup uses auto enrollment of certificates with the certificates being supplied by the Certificate Authority (Ca) on the WinServer.

The RT-AC86U successfully installs the Let's Encrypt certificate or the CA certificate that does not have a SAN specified. Without the SAN the Edge browser rejects the certificate.
Once a SAN, using "DNS", is specified the certificate appears to load. There are no errors in the routers log file. Yet it does not show up in the the Server Certificate Window.

These are the purposes of the CA Certificate
[1]Application Certificate Policy:
Policy Identifier=Server Authentication
[2]Application Certificate Policy:
Policy Identifier=IP security IKE intermediate
[3]Application Certificate Policy:
Policy Identifier=Client Authentication

These are the purposes of the Let's Encrypt Certificate
Server Authentication (1.3.6.1.5.5.7.3.1)
Client Authentication (1.3.6.1.5.5.7.3.2)

Any thought on what may be stopping the router from actually using the certificate?

Kind regards