Why do I lose connection when using application that uses WiFi?

[AC Question]

I have a Samsung galaxy S6 which was working perfectly but after updating it from lollipop to marshmallow, now I cannot use application that uses WiFi (for e.g Viber and Whatsapp).

When I call someone on whatsapp I get connected with the other person but always lose connection after 5 to 10 seconds.

I have recently discovered that when I activate my ultra power saving mode, I don't lose the connection but I cannot use any handfree devices to talk to the other person because the connection will be lost.

I would like to know if there are some solutions to this matter? Can you help?

 

[belodion]

First, have you tried a Cache Partition wipe?

 

[Tarox]

Hello there, I'm having the same problem, and I found out that the WIFI internet disconnects on screen timeout, despite having allowed my WIFI to be on while screen is off. I have tried the Cache Partition Wipe, but the problem still persists. This happens with every application or game that is being run. As soon as the screen turns off, WIFI disconnects.
In case of using applications like whatsapp, the call disconnects.

 

[Tarox]

Hello there, I'm having the same problem, and I found out that the WIFI internet disconnects on screen timeout, despite having allowed my WIFI to be on while screen is off. I have tried the Cache Partition Wipe, but the problem still persists. This happens with every application or game that is being run. As soon as the screen turns off, WIFI disconnects.
In case of using applications like whatsapp, the call disconnects.

I would like to add that even though the connection is lost when screen turns off, I still can receive notifications from applications the require internet. Upon connecting whatsapp to the PC, i can see on my pc screen that when the phone's screen (s6 edge) is off, the pc displays internet connection as on and off and on and off...