So I just got the S21U today, and everything is wonderful so far, but could not figure out how to make sure whatsapp stays running in the background....
Background usage limits = put unused apps to sleep is OFF
sleeping apps/deep sleeping apps/ never sleeping apps is 0
I went into Optimise Battery Usage, and made sure NONE of the apps or services are enabled (so no optimization for anything!!!)
I even tried, enabling Battery optimization, and then adding whatsapp to NEVER sleeping apps. (did not change the behaviour)
"Allow background activity is selected" .. (I tried turning on and off Put unused apps to sleep) IT is now off, as it made no difference.
On all my other phones this seems to be working, never even had to do any of these settings.
The only thing that makes sense is Power Saving MODE OFF! but the description udner it...
Learning usage patterns...
Background network usage, syncing, and location checking will be limited and motion smoothness will be changed to standard.
I work all day and I need to be online on WhatsApp, what am I going to do, set the screen to never turn off so that the device is awake 24/7?
Anyway, whatsapp just recently update their apps and provide a new beta-feature called "Multi device beta", this feature will provide you the ability to use web.whatsapp.com without the phone being need to stay "online"...
this update should have solve this issue
i thought the program is open for everyone out there, since almost all my friend have accessed it.
yes i don't understand samsung's application management even the slightest. i don't even know if this issues only happening on s21 series or is it also happened on older series. Looking how majority of android user uses Whatsapp they should've fixed the bug ASAP, but then again perhaps there's not enough complain for them to notice this issue.
I hope your issue is solved and if not there i'm giving you few steps that will help you to solve this issue. Firstly, Clear cache and data (take backup) and then login. Now, Go to your device setting then on network and remove data restriction over WhatsApp if enabled.
Thanks. The problem is solved.