Open your phone's Settings > tap Network & internet > Data usage > turn Mobile data on. Open your phone's Settings > tap Apps & notifications > WhatsApp.
As long as you haven't exceeded your data limit or you're connected to a free Wi- Fi network, your carrier shouldn't charge you extra for messaging over.
Open your phone's Settings app > Apps > WhatsApp > Data usage. Make sure background data is not restricted. Repeat the above steps for Google Services.
This is not an authorized app from WhatsApp and could breach the terms and For that, you'll need a SIM with data roaming, not just chat.
Did You Know WhatsApp Could Be Used Without An Internet Connection Too? Radware examines the state of application security. . And, as of now there is no such kind of channel through which these data packets transfer from one end.
Make sure you did not activate the restricted background data usage feature for Update your software or re-install the app on your phone.