Why isn't my Lenovo a6000, on Vodafone 3g, Whatsapp Hike not working over mobile data, only on wifi?

[AC Question]

lenovo a6000 on vodafone 3g,whatsapp hike not working over mobile data.working on WiFi..help me

I have using lenovo a6000 with Vodafone 3g. WhatsApp hike messenger are not working on mobile data..it shows network error or no internet connection..help me plzz