FIX: SSL VPN connection is down in FortiClient (Permission denied -455).
If you are unable to connect to your workplace using FortiClient due to error "SSL VPN connection is down", this guide provides step-by-step instructions to fix the problem.
Problem in details: When users attempt to establish a VPN connection through FortiClient, the connection is immediately dropped and a pop-up appears from the FortiClient notification area stating "SSL VPN connection is down" with an error of "Permission denied (-455)" in the notification logs.
The "SSL VPN connection is down" error message is FortiClient, may appear for one of the following reasons:
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Internet connectivity issues.
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Authentication issues.
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Invalid VPN connection configuration on FortiClient.
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The VPN server may be unreachable.
- Outdated version of FortiClient VPN
How to FIX: FortiClient VPN "SSL VPN connection is down" (Permission denied. -455).
Step 1. Check Internet Connectivity.
Make sure you are connected to the internet and try visiting a few websites to confirm.
Step 2. Reset User's Password in Active Directory & Unlock Account (LDAP)*
In my experience, the "SSL VPN connection is down" error usually occurs due to invalid user credentials (username/password) and an easy approach to verify if this is the cause of the problem is to connect to the VPN using another account.
Specifically, in AD environments where authentication is performed via LDAP, the reported error occurs if the user's password has expired or the user has been locked out of AD due to too many invalid login attempts.
* Note: If you receive the error mentioned without using LDAP, then the username/password is likely incorrect or expired. So, make sure the username and password are correct and skip to the next steps.
In such cases, when the VPN authentication on FortiClient is performed via LDAP, the "SSL VPN connection is down" problem is solved by resetting the password of the affected user in Active Directory and unlocking the account. So, even if the user's password hasn't expired yet, do the following:
1. Open the Active Directory Users and Computers in AD, right-click on the user who is experiencing the "SSL VPN connection is down" error, and select Reset Password.
2. On the 'Reset Password' window, type a new password for the account, check the Unlock the user's account checkbox and click OK.
3. Now ask the user to reconnect to the FortiClient VPN. *
* Important: In latest versions of FortiClient VPN, the username is case sensitive.
Step 3. Review settings of the VPN Connection in FortiClient.
Another cause of the FortiClient error -455 is the invalid VPN settings, So, iIn FortiClient, edit the VPN connection settings and ensure that you have specified the correct Address and Port of the Remote Gateway (VPN Server/Endpoint).
Step 4. Make sure that VPN Endpoint is reachable.
1. Open the command prompt and issue the following Telnet command to verify that the VPN server is accessible and its port is open:
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telnet vpnserver.yourcompany.com PORTNUMBER
* Related article: How to enable telnet command in Windows 11/10.
2. If the cursor flashes on a black screen after giving the above command, it means the connection is successful. In this case, proceed to the next step. Otherwise, if after running the command you receive the message "Connection failed", make sure that you have specified the correct VPN server name and port and that you have not blocked the port in the Firewall.
Step 5. Update FortiClient VPN Client.
Another cause of the "SSL VPN connection is down" error is an old version of FortiClient. So go ahead and do the following:
- Uninstall the current version of FortiClient and reboot your PC.
- Install the latest version of FortiClient and then try connecting to VPN again to see if the problem persists.
Step 6. Resolve the "SSL VPN connection is down" error from the error logs.
If you followed the steps above and are still unable to connect to the VPN, open the FortiClient Notifications (logs) to see a more detailed description of why you are receiving the error "SSL VPN connection is down". Then, take a look at this FortiGate article which may give you additional help to solve the problem.
Conclusion:
In conclusion, the FortiClient "SSL VPN connection is down" error message occurs either due to incorrect SSL VPN configuration on FortiClient, lack of internet connectivity, or invalid credentials.
That's it! Let me know if this guide has helped you by leaving your comment about your experience. Please like and share this guide to help others.
