Why does Teams keep disconnecting or dropping calls?

Teams is sensitive to connection quality in a way that email and browsing are not. A connection that feels fine for everything else can be unusable for calls, because what matters is consistency rather than speed.

Two quick tests:

• Plug into a network cable. If calls are stable on a cable and drop on Wi-Fi, the problem is wireless, which is a fixable design issue rather than something wrong with Teams.
• Notice when it happens. If it is always mid-morning or always when several people are on calls at once, you are running out of upload bandwidth. Most business internet is advertised on download speed while calls are limited by upload.

Other things we check: whether a VPN is routing your call traffic the long way round, which is a very common cause and entirely avoidable; whether your firewall is inspecting call traffic it should be letting through; and whether the laptop is simply old enough that video is overwhelming it.

If it is only one person, start with their Wi-Fi and their machine. If it is everyone, it is the network and we should look.