Help with error "...may be caused by a mismatch in the TLS version. ..."

[spalding]

Hello folks,

I am trying to connect to my work VPN server using FortiClient v. 5.6.2.1117 on Windows 10 x64, but every time I enter my username and password, it says "Warning - Failed to establish the VPN connection. This may be caused by a mismatch in the TLS version. Please check the TLS version settings in the Advanced of the Internet Options. (-5029)".

I have checked the Advanced panel under Internet Options, which has checkboxes for "Use SSL 3.0", "Use TLS 1.0", "Use TLS 1.1", and "Use TLS 1.2". When I first checked, the boxes for SSL 3.0 and TLS 1.0 were unchecked, and TLS 1.1 and TLS 1.2 were checked. I tried checking TLS 1.0 in addition to 1.1 and 1.2 and restarting my computer, but it still fails. I have tried several other combinations (like unchecking 1.1 and 1.2, so only 1.0 was checked, or checking only 1.1 or only 1.2, etc.) to no avail. I have also tried uninstalling and re-installing the FortiClient app with no success.

This started after my computer told me it needed to restart to finish installing some Windows updates, specifically KB4093112 (2018-04 Cumulative Update for Windows 10 Version 1709 for x64-based Systems). I had also just installed Visual Studio Build Tools 2017, in case that may be pertinent.

I am also emailing my workplace's computing services department in case they have seen this issue before, but any assistance would be much appreciated.

Best Regards,

Matt S.

[bobm]

I'm seeing the same type of issue, but just trying to get to secure websites through a browser (Edge, IE11, and FF all do it).

[emnoc]

Okay are you  using the forticlient or web-portal? Are you going thru a proxy ? Have you ran diag debug application sslvpnd -1 ?

What do you have enabled on the  SSLVPN  as far TLS versions ?

 try ssl-tools https://ssl-tools.net/webservers

( you will need a FQDN )

Ken

[yukimochii]

Hello, guys

Sorry for kind of necroing the thread.

Have you found any solution to this problem? One of my external vendors is having the same symptoms as the OP.

[razer8388]

Have u try to check at security levels at internet option site? i'm facing this problem before which is related with the security level at internet option. Once i reset it, the problem solved.

[bobm]

It's a MSFT issue - we have come across it a few times too.

https://www.computerworld.com/article/3298501/microsoft-windows/2-undocumented-patches-from-microsof...

[Sudarsan_Babu]

Hi,

Its seems to windows patch issue . 

Can you please refer the below link. 

https://www.computerworld.com/article/3298501/2-undocumented-patches-from-microsoft-may-solve-the-18...