There was a problem when trying to log in to your Bitrix server using the desktop application. Gives the message "incompatible server?". What to do?

Question

Bitrix24

I have my own Bitrix server on linux. Through the browser everything works fine, updated ssl, everything works with https. I'm trying to log in to my Bitrix through the desktop application, I specify the correct address, login and password, respectively, too. As a result, the message "incompatible server?" appears in the top window. I tried to set compatibility, I tried to enter a direct IP address of the server, nothing helps. I opened the page code and found the following error
"Wrong response format: Unexpected token '<' ([Error] Call to undefined method Bitrix\Intranet\Util::isIntranetUser() (0)
/home/bitrix/www/desktop_app/login/index .php:189
#0: isAccessAllowed()
/home/bitrix/www/desktop_app/login/index.php:86
) "
Found this php file at the specified path.
Can anyone suggest what to do?
PS For "specialists" who do not know that on Windows, as well as on other operating systems, there is only one BITRIX24 desktop application, the stump is clear that the systems are different, etc. I asked a specific question. I need a specific answer. No need to ask and write: Why the application, you need to update the application, etc.

https://www.bitrix24.ru/features/desktop.php here is a link to the application for connoisseurs.

Answer 1

What app? And why is there an app?
most likely Bitrix has been updated, you need to update the application

Answer 2

Maybe an antivirus?

Answer 3

• What version of Bitrix24?
  
• When was the last update? Have you updated to the latest stable or beta? Was the update successful?
  
• Are there any customizations? Or third-party developments/modules?
  

You can put the contents of the following files on pastebin:

/home/bitrix/www/desktop_app/login/helper.php
/home/bitrix/www/desktop_app/login/index.php
/home/bitrix/www/bitrix/modules/intranet/lib/util.php

I assume that one of several options happened:
- The web service (and php settings) is incorrectly configured
- Modification of the kernel or program code