In our previous article, we have discussed the most common VPN errors encountered by users on multiple platforms. In this guide, we will discuss 5 more common VPN error codes that users face and how to resolve them. Scroll down for more details.
1- VPN Error Code 789
*Error Message: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.
This is a very common VPN error that occurs when you try to connect to your VPN using L2TP/IPsec protocol. If you come across this error, it means that a processing error occurred between the security layer and the VPN server it is trying to connect to. The reason for this error is mostly because the operating system is either not compatible with L2TP or that L2TP is not properly configured on the operating system.
1- Restart your VPN client.
2- Enable IPsec on your computer.
3- Make sure that the certificate used is correct on both client and user sides.
2- VPN Error Code 0x800704C9
If you ever encounter VPN error code 0x800704C9, it is because there are no SSTP ports available on the server. This error should not be ignored to avoid system slow down or eventually total crashing.
In order to resolve error code 0x800704C9, you need to make sure that there are sufficient ports on the RAS server that are configured for remote access. You can verify this, by following these steps:
– Open the RRAS (Routing and Remote Access) MMC Snap-in.
– Expand the server, right-click on “Ports“, and then click Properties.
– Click on WAN Miniport (SSTP) from the Name List, and then click Configure.
– Modify the number of ports in the Maximum ports list as suitable for you, noting that there are 128 ports available by default.
– Click OK.
3- VPN Error Code 13801
Error Code 13801 occurs with VPN connections that use IKev2 when IKE authentication credentials are rejected. There are several reasons behind this error:
– IKEv2 certificate is expired.
– The trusted root for the certificate (needed to validate RAS) is not present on the client.
– The subject name (VPN server name) of the certificate and the remote computer do not match.
– The certificate lacks the required Enhanced Key Usage (EKU) values.
1- The certificate installed on the remote access server should have the correct values.
2- The root certificate on RAS server that is equivalent to the server certificate must be installed on the client computers in the Trusted Root Certification Authorities per-computer certificate store.
3- You can use the same certificate for SSTP connections for IKev2 as well, as long as it matches the CN and EKU requirements.
4- If you still encounter error Code 13801, then you need to contact your VPN client administrator to verify resolve this issue for you.
4- VPN Error Code 0x80072746
This is a very common VPN error that occurs when the remote host forcibly closes an existing VPN connection. This happens if the device’s certificate is not installed on the VPN server or the device’s certificate attached to HTTPS is not present on the VPN server.
1- You need to communicate with your VPN administrator to make sure that your device’s certificate is installed on the VPN server.
2- You need to make sure that the certificate binding to the HTTPS is installed correctly. You can do this by running the following command: “netsh http show ssl”.
5- VPN Error Code 720
*Error message: No PPP control protocols configured.
Users who use VPN on Windows may encounter error code 720 which occurs when their computer does not have the sufficient protocol to connect with the RAS server. This could also happen if the RAS is not configured correctly on the computer.
Make sure that the VPN protocols used are compatible with the server. In order to carry out this process, you need to follow these steps:
1- From Start menu, go to Control Panel and click on Network Connections.
2- From Virtual Private Network, right-click on the VPN connection, and then click on Properties.
3- Click on the Networking tab found in the Properties dialog box of the VPN Connection, and check to make sure that the protocol you have matches with the one that is run by the RAS server.
**If the protocol you have does not match that run by the RAS server, then you need to add the protocol. You can do this by following these steps:
– Click on Install followed by another click on Protocol, and then click Add.
– Select the protocol that you want to install, and then click OK.
– Click on Close in the VPN Connection Properties dialog box.