@Luo2020 

I have an A20, and I had similar problems with Zoom. Message is not quite the same, but as I recall something along the lines of 'slow network connection' that would pop up randomly and disappear almost immediately. Never consistently either, could go days without seeing it.

Now it doesn't happen, or I haven't seen it since my ISP speed was changed from 100Mbps to 400Mbps.

I don't know if that is 'the fix' or not, and never used the MS program. If it is an Internet speed issue (or load on it), I'd assume I would have the same problem with the MS program too.

It might be interesting if you could use Zoom as a test and see if that has a problem for you as well?

One thing I would suggest, take the Switch out of the equation. Connect direct to the router as a test (if you can).

@Luo2020 

Might want to Google "bad network connection microsoft teams". I see some complaints about this, some quite recent.

May not be exactly what you see or are experiencing, but there are some suggestions. Like this site, https://www.equiinet.com/post/how-to-improve-call-quality-on-microsoft-teams

@IrvSp Thanks for the suggestion. I don't have Zoom on my work laptop, but my wife had the same issue with her laptop using Zoom. We also didn't have the problem before with an old Netgear router, which is why I suspect the bad network connection has something to do with the new router.

@IrvSp I did a Google search and found a long thread with 100 replies. There are many people experiencing the same issue and have tried different solutions but none of them really works. There seems to be some firmware issues with either laptop or router, or incompatibility between the two.

https://answers.microsoft.com/en-us/msoffice/forum/msoffice_o365admin-mso_security-mso_o365b/microsoft-teams-kills-all-network-connectivity/b11960f6-6dfe-4bd8-81f3-286b07de3134?page=10

@Luo2020 

Yeah, but if everyone doesn't have the same ISP speed, router, and h/w attached to the router with the same level of OS, it is hard to pin it on one thing as the cause.

Try Zoom or FaceTime, or any other connection program, like Team Viewer or similar programs and see if they drop. Not that if they do you'll be able to pin it on anything specifically. If they don't, well, it could be the application itself?