Your 920 was not dual SIM. Your 950XL is dual SIM. WP does not support VVM on dual SIM devices.Same here. I used an AT&T branded (but unlocked) Lumia 920 on T-Mobile, and never had any problems with VVM. I put the nano-SIM in an adapter, made sure VVM worked with it on my 920, swapped it over to my 950XL, but no dice. VVM seems to be refusing to work. I've tried all the tricks I've seen listed. Pressing the VM button, manually calling my VM, creating VM's from other phones, etc. No luck.