Audio drops out now and then

[ENOL]

I've been livestreaming bikeclasses once a week for 5 years to members. Everything has worked fine untill now.. I've made no changes in OBS .
The last 2 sessions I had 10 online members watching and for 3 of them the audio drops out (and 'hacks') now and then. The other 7 had no issues.
The same 3 members have watched my colleges livestream with no issues. The video looks fine - no 'drop outs' - and the recording as well.
Can anyone explain to me what could possible be the reason?
I have a microphone and a program showing the 'session', from where the music comes. I.e. I capture the music from the Desktop.
I've made NO changes in the settings -and they have been joining my classes with no problems for a long time - and suddently this happens??
Thanks in advance for your help :-)

 

[Lawrence_SoCal]

If recording and some viewers were fine , then issue is entirely on the watching (client) side. Most likely (99%+ sure) nothing for you to do/fix.

As for watching (client) devices? mobile, or PC? cellular or WiFi connection? bandwidth on that connection? How recent has since last device reboot?
- basically watching users need to fix their device/connection (both local and WAN), most likely.

As for suddenly - you are using a computer/devices that get regular operating system updates... system is changing constantly (because it is configured, by default, to do so). Microsoft has been known to be getting worse in terms of update/patch quality in recent years

Most likely unrelated, but you are using a wireless mic right? and no monitoring of associated wireless spectrum [very rare]? with no monitoring, you have no idea (other than if you can hear impact in room), if interference or other issue. And typical spin class room isn't quiet, so plenty of audio mic pickup problems might not be immediately obvious, in my experience