my Instagram wont work without wifi. WHAT DO I DO

Go to Settings/Cellular and turn in the switch for Instagram.

Just to let everyone know, the mystery is solved. The people at the AT&T shop yesterday forgot to activate my phone! So when I went to make a phone call today over wifi, I got a message to activate it. So all is back to normal now. Thank you for your suggestions and perhaps this may help someone else who may be having the same problem. Have a great rest of your weekend and Happy Valentines everyone!

Omg thank you so much 😊. I have been trying to fix this issue for a while... even called ATT, but the rep was unable to fix it with all of the things she tried.. I was getting ready to into the Apple Store and then I found you.. omg you are the best! Please have wonderful holidays because you deserve it!! 😊

apps use either phone data or wifi. without either they wont work at all no matter what you do

But mine used to with Data on my iPhone 6 but since getting my iPhone 7 today it won't and will only work over wifi. This is obviously not right.

Thanks Lawrence I checked and the switch for Instagram is already on, so still a bit of a mystery.

Thanks for the followup!