Hello when I open the game (I use WT Launcher) it updates the Battleye service and then I get the error that the update failed. Check your internet connection or check your firewall. I use Kaspersky Plus as an antivirus program. In my first try I tried disabling the antivirus and there was no problem. 2-3 days have passed and today when I tried to update I disabled Kaspersky again but this time it gave the same error. So I realized that the source of the problem is not Kaspersky. I tried every method such as adding exceptions to the Kaspersky firewall etc. but nothing worked. I can’t think of any other method anymore. I couldn’t find any resource about this on the internet. Has anyone experienced a similar problem and can anyone help?
If you are on windows have you added exceptions to the built in windows firewall as well? I think it gets automatically activated when you disable any antivirus programme you have installed.
In my Windows firewall, War Thunder 3 or 4 are already approved, but just in case, I did as you suggested and added a new rule and included the two executable files from the installation folder as exceptions. However, I’m currently facing another problem, which I’ll address in a separate thread.
I would add the “aces” executables to the firewall exceptions as well yes.

Yes, I’ve attached these two executable files. Just in case, I’ll also attach Kaspersky now, but I had attached them before and nothing changed.
If you’re still having issues then i recommend contacting support. You can find support and instructions on how to contact them here: https://support.gaijin.net/hc/en-us/articles/360000262858-How-to-submit-a-support-request