Why does sms TO address changing to email address?

[JeffreySp]

For only one of my contacts, every time i send a text from my Samsung S6 Sprint phone to that one verizon mobile number it auto converts to an email gateway address ie mobile#@vtext.com. i can see address auto covert in history soon after sending even before getting any reply. Only happens for that one #. I tried deleting/re-enteringcontact but no help. Any ideas how to make it stop?

 

[Paul Thigpen]

I'm having the same issue, but with three contacts and I'm on T-Mobile with an S6. T-mo couldn't figure it out so they gave me a new S6 and I still have the same issue so it doesn't seem like it's the hardware. My company makes me use Air Watch app for exchange server emails. Do you use Air Watch too?

Also, once it converts to @vtext.com it also converts it to an MMS. Then randomly it won't deliver the message at all and I have no idea if it went through or not...very frustrating...