Altar connects people through their browsers so if there is an issue with someone's audio and video connection, it is likely do to blocked permission in the browser.
You can resolve this by clearing your cache and cookies or by switching browsers.
While Safari and Edge are technically supported in Altar Live, they often present more WebRTC based issues. It is often easier use Chrome or Firefox so you may consider switching to these browsers.
Are you curious about the community and engagement Altar Live values? Check out: What Does it Mean to Have an Interactive Church Service?