No internet when I lock my phone

[DDr23]

I have galaxy a8 (2018), whenever I lock my phone, after some time suddenly internet is not working.

I dont get notifications from chat apps etc. and also for example if Im logged in with WhatsApp web, some time after locking my phone, I get no connection error on whatsapp web, when I unlock my phone suddenly i get all the notifications and it recconects to whatsapp.

I know for sure its not just with whatsapp, I dont get any notification from an internet depanded app when the phone is locked.

I checked and data saver is off, notifications are allowed, background activity is allowed, background data usage is allowed, Put app to sleep option disabled in device care, of course do not disturb disabled.

It is also not depanded on WiFi/Mobile data, I mean it happnes on both.

Any ideas??? 

It gets me crazy!!

Model - SM-A530F

Android version 9

One UI version 1

It is up to date.

[Alireza MS]

I mentioned the solution above.

[Stephers1976]

@chiragmittal @alireza MS this hasn't worked for:( I literally with to bin this phone!!

[Stephers1976]

This hasn't worked for me 😞

[Alireza MS]

Are you sure you did it correctly? If you have the same model with me (A52) it must work.

Check the steps again, make sure to toggle off the battery optimization swicth for your messenger and VPN apps.

[Stephers1976]

I have s20 fe.. I've followed your instructions and defo switched off optimising. In that same section, the Allow background activity is greyed out.. argh

[Stephers1976]

Doh we have different phones but ty for your help so far x

[Exter-dg]

I have A52 but can't find these two -

4. Tap on Optimize battery usage.

5. At the top of this page, there is a menu which is set to "Apps not optimized". Tap on that and select "All".

going into battery shows three options - unrestricted optimised restricted,

i use whatsapp web and the wifi disconnects after some time of locking the screen. I again have to turn on the screen to use it.

[Alireza MS]

Hi, sorry for latancy.

Here I posted some screenshots, just follow them:

1. Go to App Info page (Any app that has connetcion problem)

2. Tap on "Optimize battery usage"

3. Open the drawer menu and choose "All". Then turn off the toggle for that app (and any other app which has connection problem when screen is off, such as messengers, VPNs and etc.

This method worked for me, I hope it to helpfull.