I uninstalled the app without disconnecting from Xero

If, for whatever reason, you've uninstalled the app without explicitly disconnecting from Xero, as part of the uninstall process, your connection between Shopify and Xero will be automatically disconnected.

If you'd like to double-check this, go to your Xero account.

Select your store, and click on "Settings".

Under "Organisation Settings", click on "Connected Apps".

It should show that there are no connected apps.