[jackson1way]

I have the same issue with the web app (using an iPhone). What I figured out is, that you don't need to unlock the screen to make the web app reconnect. All you need to do is switch on the phone (without unlocking), so just give the home button a little tap and 2-3s later the web app is reconnected. Not a great solution, but well...

[balladeer]

You are right. That sometimes works. But what I've noticed, maybe it's some issue with my set up - not sure, that often the WhatsApp desktop/web app doesn't connect for 1-2 minutes even after I have unlocked (or woken) my phone - so I just click on WhatsApp app on phone anyway and let it reconnect. Android and iOS both are pretty strict on background tasks these days. I hope battery tech catches up with the speed at which apps' resource appetite is growing.