Why won't the internet work while on a call HTC One M9 on Verizon?

[AC Question]

Internet won't work while on a call HTC One M9 on Verizon

When on a call I cannot use my mobile data. I tried switching the network from Global to LTE but then call don't go through at all. Any suggestions?

 

[VerizonDroidMotoX]

Re: Internet won't work while on a call HTC One M9 on Verizon

Do you have Advance Calling enabled?

 

[VerizonDroidMotoX]

The HTC One M9 will launch with Advanced Calling1.0 capabilities. You can enjoy HD Voice and Video Calling to other compatible Verizon smartphones. Activating this feature also enables simultaneous voice and data use, so customers can talk and surf the web at the same time.

Check it out Advanced Calling 1.0 - Verizon Wireless - Verizon Wireless