Welcome to the community!
Hmm, that's strange... Are you able to use other data? Do you receive any error messages when trying to connect to WhatsApp via network? Does it happen everywhere or only at certain locations?
I don't think WhatsApp is blocked by the networks. I haven't had any issues using the app without Wifi. I also just accessed and sent a message via the networks to test and everything seemed to transmit/receive okay.
Have you verified your WhatsApp settings are enabled for cellular data usage? Does your phone have any settings to limit cellular data for specific apps? Is it possible those settings are restricting data for WhatsApp?
Hope this helps 😀