Ideas for why voices are being picked up other than microphones

[chamel]

Hi, I hope someone can help with this. We have been using OBS for live-streaming for a few years in our small church. I am new to the team so wasn't there when the system was set up by our previous pastor. Just recently, something has changed in settings somewhere. Our voices behind the scenes especially can be heard as well as the congregation before church actually starts, in the recording. We have a sound board with audience mics turned way down. It is hard for us to figure out and to test out possible settings. I'm guessing the actual computer microphone? Does anyone have any ideas to try? Thanks so much