解决方法：https://github.com/laravel/passport/issues/221
In your oauth_clients table, do the values you have above exist exactly as you have them in your database?
oauth_clients
1 | id - 3 |
If it doesn't exist exactly like that in the database for passport.dev then it will throw the invalid_client error. Please be sure to check that and we will see if any further investigation is needed.
还需要查看 oauth_clients 表的 password_client 是否为 1