When you move your Dataverse environment from one geolocation or tenant to another, associated websites to that organization won't move automatically. Also, since your organization has moved, any website associated with that organization won't work and will throw an error on startup.
To associate your website again to relevant organizations:
Reset your existing website host from the existing geolocation or tenant by following the steps in Reset a portal. This will delete your associated website resources and the website URL won't be accessible after the operation completes.
Once your existing website is reset, go to the new tenant (or to the new geolocation of the existing tenant) and provision a website available there.