I am using external livekit can confirm the issue. Most probably fluxer doesnt have this issue cause of the wildcards but for a selfhosted instance adding "Voice Servers" via the admin UI the CSP breaks it.
Please note that this issue has more to do with fluxer CSP directive for voice servers than Netbird. I am not using Netbird but my livekit server is still hosted on a different domain. (Not speciifc to this issue but the Turnstile challenge domain for example is never set in CSP, at least in V1 Docker image so Turnstile challenges also breaks) .
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Comment by @Buco7854