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0xCAA82EE7 Severity: Medium

Could not reach the server

Teams cannot reach Microsoft during sign-in. Classic network symptom, often caused by firewall or DNS.

Last verified:

Affected systems

windows macos

Symptoms

  • 0xCAA82EE7 shown on launch or sign-in
  • Teams reports 'Cannot reach the server'
  • Web client also fails

Possible causes

  • No internet or DNS problems
  • Firewall or antivirus blocks Teams endpoints
  • Captive portal (hotel, cafe) not yet accepted
  • IPv6 enabled but misconfigured

Solutions

1.Verify basic connectivity

  1. Open https://teams.microsoft.com in a browser - does it load?

  2. If not, test the connection with another site.

  3. On public networks (hotel Wi-Fi) accept the captive portal terms in the browser first.

2.Ensure Microsoft 365 endpoints are reachable

  1. Open a terminal and test resolution.

    nslookup teams.microsoft.com

  2. If it fails, try a different DNS server (e.g. 1.1.1.1 or 8.8.8.8).

  3. Reboot so Teams rebuilds its DNS cache.

3.Check firewall and antivirus

  1. Disable antivirus temporarily and try again.

  2. Add Teams as a firewall exception if the app is blocked.

  3. On corporate proxies, ask IT to allowlist the Microsoft endpoints.

Microsoft offers an official Network Assessment Tool for exactly this class of errors. If the issue repeats on a specific network, ask IT to run it.

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