Issue from mobile builder plugin
We have 2 plugin app builder and mobile builder for now the cart and checkout not working well when you install both. Try deactivate mobile builder and run again.
Issue from JWT Authentication
You can flow this to config App builder working along with Jwt Auth https://appcheap.io/docs/cirilla-developers-docs/troubleshooting/jwt-authentication-for-wp-rest-api-plugin-installed/