Wifi and mobile data not working on snapchat and WhatsApp but working on other apps

I have an iPhone 11 and recently the phone is connecting to wifi and mobile data and this is working on other apps such as Facebook & Gmail. However, neither wifi nor mobile data are working for Snapchat or WhatsApp. I have tried deleting and reinstalling both apps but it is still saying cannot connect to internet when I go on both of these apps. Please tell me how to fix this. I need WhatsApp for my job, so this is a significant issue. Currys backup and TikTok are also not connecting to wifi or data. And there is no wifi symbol shown in the top right corner of the screen even though the phone is connected to wifi.