Random disconnection from website

[REDACTED]

We propose online games using websockets, and we noticed that websockets are disconnected randomly after a few seconds for no reason.

After investigations, we noticed that 100% of users encountering this problem use the avast antivirus. People not using AVAST have no problem at all. Not all the person using AVAST have this problem but hundreds of persons are concerned by this problem on our website.

This problem started at the beginning of April 2017.

Details of the problem:
We use a NodeJS server and the socket.io library.
The connection of the websocket is normally done, messages are exchanged between the GWT client and nodeJS, but sometimes the websocket cuts in the middle of receiving a message randomly.

Having not changed the configuration of the NodeJS / socket.io server and the GWT client for several months, and this problem only affecting users using the AVAST antivirus, we suspect a problem introduced by the last update of the anti-virus.

Could you please help us to solve this problem ?

[Eddy]

What OS/SP are they using ?
What exact version of avast do they use ?
Do they have any other security (related) software installed ?
Do those users have the latest fix for the problems with the port scanning installed ?

[REDACTED]

Mainly windows 7/10
Several versions, but 17, and mainly the free version.
Most of them have anything else, I have sent a questionnaire.
Our user are 50/60 years old average, they are not familiar at all with computers and I won't be able to make them difficult manipulations (even 5 clics is difficult )

Thanks a lot

[Eddy]

You could ask them to disable the avast shields one at a time and check each time after disabling one to narrow down the cause of the problem.