Just in case it may save someone's day, I want to share an issue I resolved earlier today.
After running a Composer update, the API routes were failing authentication with Error 401! After some hours l hours of desperate search, I decided to try and update laravel/passport after which all was working fine again.
$ composer update $ npm run dev
The above included an update of Laravel 6.18.25 to 6.18.35 that seems to have broken all auth:api routes; failing with “401”
$ composer require laravel/passport $ npm run dev
This updated Laravel Passport from 8.4 to 9.3, which fixed the issue.
Would there have been a way to avoid falling into this update trap?