This error can be caused by the Office sign-in flow on Windows 11 Home, even when internet access is working normally.
Try these steps in order:
- When Word asks whether to sign in to all apps and websites on the device, select No, sign in to this app only.
- This avoids device registration, which can trigger error 2604.
- Check the work or school account connection in Windows.
- In Windows Search, open Access work or school.
- If the correct account is missing, select Connect and add it.
- If the wrong account is listed, select it, choose Disconnect, then select Connect and add the correct account again.
- Clear stored Office credentials.
- Open Control Panel > User Accounts > Credential Manager.
- Under Windows Credentials and Generic Credentials, remove entries related to Microsoft 365 or Office.
- Restart the PC, then open Word and try signing in again.
- If multiple Office or work/school accounts were previously added, remove extras.
- Go to Settings > Accounts > Email & accounts.
- Remove extra work or school accounts.
- Then restart and sign in again with the intended account.
- Verify the network connection status in Windows.
- Go to Start > Settings > Network & internet.
- Confirm the connection status shown at the top.
If the problem happens only on a wired connection and not on Wi‑Fi, update the network card driver first. If that does not help, disable IPv4 Checksum Offload:
- Open Control Panel > View network connections.
- Right-click the network adapter > Properties > Configure > Advanced.
- Select IPv4 Checksum Offload and set it to Disable.
- Select OK.
- How to fix error 2604? "No network connection" When I try to sign in to Microsoft 365 Business apps from Windows 11 Home - Microsoft Q&A
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