Nebula VPN MFA - Certificate Error

I'm configuring the IPSEC client to use Nebula Cloud Auth with MFA (ATP500 connected to Nebula).  It all works well, but the webpage to enter my MFA token has an invalid certificate.  The standard security settings we use on all of our clients is to block sites with certs that can't be validated.

What's the best way to solve this problem?

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