FortiClient VPN Error 5053 5052 89%

[cis]

Hi there,

I'm getting the errors "-5052" and after updating from 7.0.x to 7.2.x it's "-5053" when trying to connect using the FortiClient VPN on a Windows 11 machine. I verified login data, deactivated 2FA temporarily. Other machines / clients (even on Win11) do not have this problem.

It is, however, possible to connect from the same client using the local admin account, so maybe something in the profile is broken.

I tried as suggested in this thread:

Steps to troubleshoot the FortiClient VPN connection issue:

1. Verify network connectivity.
2. Check VPN server settings in FortiClient.
3. Disable firewall and antivirus temporarily.
4. Update FortiClient to the latest version.
5. Flush DNS cache using the command "ipconfig /flushdns".
6. Remove any conflicting VPN or networking software.
7. Contact Fortinet support for further assistance (couldn't provide a solution either).

In addition I tried removing %localappdata%\Forticlient\ as suggested by a user, but this didn't affect anything.

I did record logs, see pastebin links below, using:

diag debug reset
diag vpn ssl debug-filter clear
diag vpn ssl debug-filter src-addr4 <client public IP>
diag debug app sslvpn -1
diag debug app fnbamd -1
diag debug console timestamp en
diag debug en

The logs:

Firewall Debug log: https://pastebin.com/kHsj6axm

Additional logs from the FortiClient:

guimessenger.log https://pastebin.com/tyKdgHkQ

sslvpnlib log: https://pastebin.com/Y5ShMCZV

I'd appreciate help.

There must be some internal reference to the error codes 5052/5053?

Are there some hidden local user files that I'm missing?

[knagaraju]

Dear cis,

Thank you for attaching the debugs.
I see the error DataVPN::getVPNSettings Failed to load REG_SSLVPN_SERVICE_PORT
There seem to be some restrictions on his PC. As it is working on other PCs.
I guess it might be one of the following:

1. The SSL VPN port is blocked on the PC. (But we do see connection requests coming to the Fortigate)
2. TLS issue.
3. Are you using some software (AV or Windows firewall) that prevents the connection?
4.  FortiClient itself could be corrupted. he can try a new FortiClient (VPN-only version)
5. The Adaption is not updated on his PC.

However you have mentioned that you have already tried all the above.
Next action plans
=============
1.)Try with your credentials on a working PC. If it works then,
2.)Re-image the OS on the PC then re-install the forticlient.

Regards
Nagaraju.

[mgoswami]

Hi, 

Error at 89% indicates an issue at the system level. 

I will suggest checking your Windows machine. Uninstall the Forticlient software and do a manual update on the Windows machine. 

BR,

Manosh

[cis · Accepted solution]

Hi guys,

I did again check and verify that I performed the steps you suggested cleanly.

1. Uninstalling AV completly
2. Reinstalling FortiClient again
3. Cleanly delete all folders in %appdata%

This time, it worked. I do have one client where I can narrow down the solution. But I guess it was 3. because I wasn't able to fully delete the %appdata%/Local/FortiClient folder with del in the powershell, as far as I remember. This time I ensured it was fully deleted.

Maybe for the devs you could tell them that an uninstall should cleanly delete all folders.

Thank you anyway and sorry. I will report back when I fixed the one missing client.

Best regards

[cis]

No. 3. was the correct solution.

Thanks guys.