I recommend starting with an OBS guide. As this is for a House of Worship, I strongly recommend PTZOptics's / StreamGeeks new OBS Guidebook (free PDF to download)
As a starting pointer, most streaming service (YouTube, Facebook, etc) work by entering a stream key into OBS. The streaming service ties that key to an account. Rotating stream keys regularly is good practice (though like most security things, people don't do it, and then suffer the consequences). So, there is no 'new address' you just need to make sure your Channels' stream key is the one in OBS. And if an admin leaves, always good practice to change stream keys regardless.
Recognize that real-time video encoding can be complicated, (and OBS provides lots of power and flexibility, with the complexity that goes with such) so there are LOTS of possible reasons why a stream will fail
- OBS update and not manually updating 3rd party plugins
- OS and especially video driver updates known to cause all kinds of issues (though usually crashing, not stream failures)
- if OBS PC running well (not pegged at 100% CPU or similar hardware resource overload), then network upload bandwidth would be a key thing to monitor/check. And that assumes no WiFi in the data path from camera or audio, to OBS PC to Internet
All it takes is one unwitting person to connect (ex Guest WiFi) have something running and consuming your (usually far more constrained) Internet upload bandwidth
See my .sig for links to OBS automated Log Analyzer (good first place to check), then how to post your log if you need more help from this forum.
And if you do want more assistance, I recommend being more specific/technical in description of the problem. "failed to live stream" can mean lots of different things. And OBS has color indicators on its status bar, which can help. So things like was OBS running ok? did the Stats window indicate encoding and transmit working, or ?? What dd YouTube's preview admin page (I use FB for our HoW, so not sure of exactly what YT's interface looks like, I'm assuming similar functionality) indicate? What about OBS PC hardware resource utilization monitoring? your internet connectivity monitoring? etc