Outlook Disconnects When Connected to VPN [8 Tested Fixes]

1. Disable the VPN connection.
2. Update Outlook to the latest version.
3. Exit Outlook.
4. Connect to a VPN server.
5. Launch Outlook.

Make sure you’re running the latest version of Microsoft Outlook. It could help resolve various compatibility issues with the software, including VPNs.

You should be able to enable updates from your Office account after opening the main menu in Microsoft Outlook.

If your Internet connection isn’t stable enough, it could be the reason why Outlook won’t connect over a VPN.

1. Press the Start button, type firewall, and select Firewall & network protection.
2. Click Allow an app through the firewall.
3. Click Change settings (you need admin rights).
4. Find your VPN service on this list.
5. Enable the Private and Public options for its entry.
6. If your VPN isn’t here, click Allow another app to locate it.
   

If you follow these steps, you will fix firewall issues with VPN traffic. If Outlook connects over your VPN now, it means there was never a problem on the email client’s side, but with your firewall.

And, if you’re using a third-party firewall, make sure to adapt the instructions we provided for Windows Defender above.

A premium VPN service like ExpressVPN shouldn’t get blocked by your firewall because it automatically creates an exception for itself when you install it.

1. Go to Control Panel.
   
2. Select Network and Internet.
3. Go to Network and Sharing Center.
4. Click Change adapter settings.
5. Right-click your Wi-Fi connection and Disable.
   
6. Connect to the Internet in Ethernet mode.

If you’re connected to the Internet in both Wi-Fi and Ethernet mode, it could result in a conflict that causes the VPN connection error on Microsoft Outlook.

To easily fix this problem, simply deactivate your Wi-Fi connection and stick to wired mode.

It also indicates that you have Wi-Fi connectivity issues, which you should troubleshoot as soon as possible to continue using wireless mode.

1. Go to Network Connections > Change adapter options.
2. Right-click your Internet connection and select Properties.
3. Double-click Internet Protocol Version 6 (TCP/IPv6).
4. Select Use the following DNS server addresses.
   
5. Set Preferred DNS server to 8.8.8.8
6. Set Alternate DNS server to 8.8.4.4
7. Click OK.

If your default DNS servers take too long to load pages, this could also cause VPN connection issues over Microsoft Outlook.

But you can solve this problem by changing the DNS servers. The servers we listed above are free, public, and belong to Google Public DNS. You can also try Cloudflare or OpenDNS.

However, if you have a reliable VPN service like ExpressVPN installed, you don’t have to worry about this issue.

1. Run Command Prompt with elevated rights: press Ctrl + R, type cmd, hold Ctrl + Shift, and press Enter
2. Copy and paste the next lines (press Enter between each line)

ipconfig /flushdns

ipconfig /registerdns

ipconfig /release

ipconfig /renew

NETSH winsock reset catalog

NETSH int ipv4 reset reset.log

NETSH int ipv6 reset reset.log

exit

Restart your computer to finish the modifications.

You can easily reset network connectivity settings on your Windows computer by flushing DNS servers and resetting Winsock.

A lot of VPN connection problems can be fixed this way.

If your router doesn’t allow VPN traffic, you wouldn’t be able to connect to a remote VPN server or accept VPN connections. It doesn’t matter if you’re trying to use Microsoft Outlook or any other tool.

In this case, you must access your router’s admin panel, look for a NAT Passthrough option, and enable it for your VPN protocol. Out-of-the-box router firmware typically supports PPTP and L2TP.

If you intend to use a VPN protocol that’s not supported by your router’s firmware (like OpenVPN), here’s what you can do:

➡️ Set up port forwarding at the router level* (not safe). But it only works with VPN server mode.

➡️ Check if your router allows you to install third-party firmware. If so, you can set up DD-WRT, Tomato, or OpenWRT (requires advanced skills). They support VPN client mode.

➡️ If your router doesn’t support third-party firmware, you can purchase a router with VPN client capability and then set up bridge mode to avoid Double NAT.

➡️ Instead of configuring router settings and risk messing up its functionality, you can just Express software to switch your protocol for OpenVPN or other within a few clicks.