I have integrated the Okta widget based approach for my Vue application.
The entire end to end authentication user flow seems to work as desired when testing with my personal developer account as well as the client’s own Okta domain account.
The client recently purchased a new tenant and after setting up the application just as done previously, the exact same authentication user flow got blocked during the callback due to a 401 response from the POST request to the oauht2/default/v1/tokens endpoint.
This request is initiated by Okta’s Vue library itself and is a part of the callback user flow. I have never encountered this error before.