Why does the Skype connection drop with error 7002 in the console?

Question

Skype

In the web version of skype (in IE11 or Edge), the status switches to offline for a short time.
Windows 10 1709 is used.
In the developer console (by pressing F12) you can see repeated errors:
SCRIPT7002: XMLHttpRequest: Network error 0x2ee2, Failed to complete the action. Error 00002ee2
And in the same console, on the network tab, you can see that it is not possible to receive a response from the following host:
Name Protocol Method Result Content Type Received Time Initiator
https://db4-client-s.gateway.messenger.live.com/v1. .. POST null 0 with XMLHttpRequest

Screenshots of the error

Apparently, the reason for this problem prevents me from using the Skype for business web client, which also constantly loses connection with the server when connecting to the conference. By the way, in it the connection goes only through the TCP protocol, although it should also go through UDP, as far as I know.
Under another user on the same PC, the problem is not reproduced.
On a nearby computer running Windows 10 1803 on the same network, the issue does not reproduce.
On many PCs in a corporate network, the same symptoms on win 10 and win 7.

Unsuccessful attempts to resolve

Проблема осталась и при подключении через разные каналы интернет.
В режиме чистой загрузки так же возникает проблема.
Пробовал сбрасывать сетевые интерфейсы (netsh winsock reset), чистил кэш DNS.
Сбрасывал настройки IE.
Переносил настройки IE с ПК где проблемы нет.
Обновлял, удалял приложения Skype.
Просил помощи у MS Community тут1(ru) и тут2(en)

Please help me to sort out this problem.
Thank you.