Why can’t I send/receive emails/ WhatsApp messages when not on home WiFi

Hi REB1951,

Thanks for coming to Apple Support Communities for help today. As we understand Mail and WhatsApp don't work when roaming is turned on. They will work on Wi-Fi.

Do other apps that use an internet connection work? For example, can you visit a website with Safari when roaming?

If it's just those two apps, is it possible cellular data is switched off for them: Check the cellular data usage on your iPhone and iPad.

Let us know how it goes.

Have a fantastic day!