why is it not working on my phone Snapchat?

If it only happens using Snapchat, I suggest that you contact their support/developer team and ask them.

Use these instructions:--> How to contact an app developer - Apple Support

Regards

Giulio

My Snapchat is not working on my IPhone XR, it keeps showing account disable

This is not an Apple app or Apple issue. Apple cannot help you.

Contact Snapchat Support and ask them to enable your account. If you have been banned, you will not be able to use Snapchat on your device.

Snapchat SupportSnapchat Supporthttps://help.snapchat.com › en-us

Snapchat is a 3rd party app, reach out to Snapchat Support -> https://help.snapchat.com/hc/en-gb/articles/14367237269780-My-access-to-my-Snapchat-account-has-been-temporarily-disabled

fyi: Snapchat hate VPN.

Snapchat is a 3rd party app, reach out to Snapchat Support -> https://support.snapchat.com/en-GB/a/blocked-network

fyi: Snapchat hate VPN.