I can no longer send vtext message from my Optimum online (Cablevision) account. Now only vtexts sent from Gmail, Hotmail, and Yahoo get through. This is a recent development.
According to Optimum the vtext message has been sent. I never get a delivery failure message. Vtexts used to show up on my old Droid Razr and Droid Raze Maxx. They do not show up on by new Google Pixel 3. Neither Google nor Optimum can help.