Why doesn’t my iPhone screen mirror to my tv?

The TV model is absolutely a part of this.

Check and update the firmware there too, as many “smart” TVs have firmware updates.

The TV will have to support AirPlay 2, or you’ll need to access the TV via an Apple TV 4K or Apple TV HD box, for wireless.

TVs with integrated support for the Apple TV app are insufficient for AirPlay 2 access.

Use AirPlay to stream video or mirror your device’s screen - Apple Support

If AirPlay or screen mirroring isn’t working on your device - Apple Support

A direct connection to the TV via HDMI usually works too, given the right cabling and adapter.

For an iPhone XS, that’s probably this: https://www.apple.com/shop/product/MD826AM/A/lightning-digital-av-adapter

About Apple Digital AV Adapters for iPhone, iPad, and iPod touch - Apple Support

Coopste3 wrote:

I have a Vizio M series Quantum purchased in Sept 2019. I worked fine mirroring up until a month ago

And what have you tried since then, and what happened when you tried it?

Firmware updates? Removed or reset the sharing configuration? Rebooted both the {whatever device you’re mirroring from} and the Vizio? Checked with Vizio support FAQs? Anything else?

What exact model of TV do you have?

~Lyssa

I have a Vizio M series Quantum purchased in Sept 2019. I worked fine mirroring up until a month ago