Whether you want to protect your online privacy or access restricted content, VPN is the ideal choice. However, it’s frustrating when you may’t set it up properly, or the connection can’t be established leading to different error messages.
While incorrect credentials are a common cause, the VPN may also not work due to server or internet-related problems. Additionally, IPv6 incompatibility, failing Remote services or network protocols, corrupted WAN Miniport drivers, and blocked ports can also cause this issue.
Before moving on with the hard fixes, let’s start with basic troubleshooting.
General Troubleshooting Tips
Whether you’re unable to connect to the VPN at all or can’t utilize the internet while being able to establish the connection, simplydisabling IPv6can sometimes do this trick.
Some VPN servers only utilize IPv4 addresses and headers and might not be compatible with IPv6.
If your VPN server supports IPv6, but you’re using large data payloads (watching live streams/broadcasts, transferring/downloading large files, etc.), this might add more space to the IPv6 header. This might be the reason your VPN keeps disconnecting.
A simple workaround to this problem is to lower the Maximum Transmission Unit (MTU) size. This way, the header space is well-managed, and there will be less packet loss and potentially no packet fragmentation. So, you may make the VPN start working without disabling the IPv6 address.
Note:Since the recommended lowest MTU size for IPv6 is 1280, I won’t advise you to adjust yours to less than that. If your VPN is still not working, reset the MTU size and know that IPv6 is probably not causing the problem.
Check for Network Adapter Issues
WAN Miniport device drivers provide alternative connection methods, including the VPN. If outdated or corrupted, your VPN might stop working or throw different errors.
To solve this, you may either update (if possible) or simply reinstall them following the below instructions:
Based on the tunneling protocol used for establishing a VPN connection, it’s essential that the necessary ports remain open.
Here’s a chart that should help you out on which TCP/UDP ports your firewall shouldn’t block:
Setup Exception for UDP
