IkeV2 mobile VPN - Policy Match Error
Hello, I'm trying to connect a Win Server 2019 machine to a Firebox VPN using IkeV2. The firebox is a XTM25. I've tried with the default IkeV2 VPN settings as well as with many edits to the config (mostly security settings) to try and get this going but still consistently encounter the same 2 errors: Policy match error and/or Unknown error occurred. Extensive searches online have turned up many results but none that have been able to help me so far. I've tried many solutions that relate to Win10 (including creating a reg key to force the system to use higher DH groups) but this proved fruitless as expected.
I am using the client profile downloaded from the Firebox to add the VPN connection to the server. I have also tried adding it manually with identical results.
If it helps- I was able to successfully create and connect a SSL vpn using the same machine and firebox.
I've verified the user account created for this connection is a member of the IkeV2 users groups on the Firebox. I've verified the external address wasn't mistyped. I've tried reverting the security settings back to defaults (have other Firebox's to review settings on for this) as well as matching the settings to an existing, fully functional IkeV2 vpn we have working on a different Firebox (different model as well, however).
I've probably missed a few details, hopefully I can find some help here and I'm more than willing to retry things I've already tried on the off chance I missed a minor detail.