How to Fix Microsoft Sign-In Error Code “0x801901f4”

The error 0x801901f4 occurs when you try to log in to a Microsoft-linked account such as Outlook, Microsoft Store, or Office on your PC or Xbox. This code indicates that the authentication process has failed because Microsoft’s servers couldn’t validate your login attempt due to issues with your current network configuration. The most common causes include incorrect DNS entries or misconfigured TLS settings, which interrupt secure communication with Microsoft’s servers.

In some cases, this error is also triggered by account synchronization failures, corrupted login credentials, or problematic Windows updates.

Now that you understand what causes this error, try the verified fixes below that have worked for many users.

1. Switch to a Public DNS

Your ISP’s DNS might be slow, unreliable, or blocking essential endpoints required for Microsoft authentication. Replacing it with a trusted public DNS, such as Google’s or Cloudflare’s, ensures faster, more secure, and regularly updated name resolution.

1. Press Win + R keys and type:

   ncpa.cpl

   

2. Right-click your active network connection and select Properties.
3. Select Internet Protocol Version 4 (TCP/IPv4) and click Properties.
4. Click Use the following DNS server addresses and enter the following:

   Preferred DNS server: 8.8.8.8

   Alternate DNS server: 8.8.4.4

5. Click OK to save the settings.
6. Restart your computer and try signing in again.

2. Use a VPN

If your ISP’s routing is blocking communication with Microsoft’s servers, a VPN can reroute your traffic through a secure tunnel, allowing stable connectivity. Once you’ve successfully logged in, you can safely disable the VPN.

1. Download and install a VPN such as Cloudflare’s 1.1.1.1.
2. After installation, click the VPN icon in your system tray.
3. Toggle the connection switch to enable the VPN.

3. Use a Different Network Connection

If using a VPN doesn’t help, try switching to a completely different network. This forces your system to use new DNS servers and routing paths, eliminating potential ISP or router-related issues. Using your mobile hotspot is a quick way to test whether the issue lies within your existing network.

4. Power Cycle and Re-Add Account (For Xbox)

Corrupted cache data on your Xbox can cause invalid authentication tokens. Power cycling clears cached data, while re-adding your account forces a new sync with Microsoft’s servers.

1. Make sure your console is in idle mode.
2. Press and hold the Xbox power button for 10 seconds until the front LED turns off.
3. Disconnect the power cable and wait at least one minute to allow capacitors to discharge.
4. Reconnect the power cable and turn the console back on.
5. Try logging in again.
6. If the error persists, remove your Xbox account and re-add it (make sure you remember your login credentials before proceeding).