Please deactivate all the 3rd party plugins and activate only theme-required plugins on the site and then check the issue. I am sure your issue will be solved. Then Activate the 3rd party plugins one by one and check which plugin is creating the issue for you.
Otherwise, if the issue still exists then keep the 3rd party plugins deactivated and share the WP admin login details of your site so I will check and give you a possible solution.
Now i reset all the checkout fields. now the error isn’t there. But I don’t want company name, country, state etc so I disabled this checkout field. When I do so I get this error. reset to default checkout field do not give this error.
Sorry to hear about the inconvenience. Kindly, please share your Site WP-ADMIN Login details in the Private Content field so that we can check this concern on your Site and help you out accordingly.