For others, who may be struggling with the same problem...
YouTube creates a new embed code for each video. So, each time you livestream a new embed code is generated.
After some experimentation, I will test this sequence this Sunday:
a. Click on "View on watch page"
b. Click on "Share" -> "Embed"
b. Copy the embed code.
Note: the text around the src in the embed code always stays the same. Only the src URL changes.
In the platform
a. http://"your church".churchonline.org/admin/events
b. Click on the event
c. Click on the "Videos" tab.
d. Update the embed codes
In StreamLabs OBS
a. NOTE: Should only have to do this step once.
i. Settings -> Stream ->
ii. Stream Type = Streaming Services
iii. Service = YouTube / YouTube Gaming
iv. Server = Primary YouTube ingest server
v. Stream Key =
b. check all of your video framing and audio levels
c. click on "Go Live"