Yes. iCloud Private Relay uses QUIC, a new standard transport protocol based on UDP. QUIC connections in Private Relay are set up using port 443 and TLS 1.3, so make sure your network and server are ready to handle these connections.

I don't have Rosetta installed, so I also needed this tip from u/GetVladimir - https://www.reddit.com/r/MacOSBeta/comments/mv2vn8/psa_to_enroll_to_the_macos_big_sur_public_beta/ PSA: To enroll to the macOS Big Sur Public Beta without the need to install Rosetta, use "sudo /System/Library/PrivateFrameworks/Seeding.framework/Versions/A/Resources/seedutil enroll PublicSeed"

No one can help you without more info on what you have , tried...

Eaton’s provided some helpful info here but it does seem to confirm the issue: https://developer.apple.com/forums/thread/683957

Private Relay targets the shuffling of IP addresses of HTTPS-related protocols I’m curious what you mean by that. (That’s not something I’ve heard of. )

Realized I didn’t specify that I was trying with popular presumably relatively bug free apps when I wrote “For every app I tried, I got an error like” Not ones I had built. So yes they had the Info plist files. I never did figure this out, but forgot to come back here.

Oops. So currently there’s no way to delete an answer that was meant to be a comment?

I noticed iCloud private relay doesn’t relay traceroute packets either but does relay some https traffic. I think perhaps it should be called alpha? Seems completely unpredictable