原始问题的回答已经输入为update-1。但它只适用于管理员用户。

Answer to the original question has already been entered as update-1. But it was only working for admin users.

实际上，在应用创建过程中，我错误地选择了沙盒模式，限制了应用只能访问应用配置页面中添加的开发者的访问权限。因此，禁用此模式后，我也可以为其他用户生成访问令牌。

Actually during app creation, I had wrongly selected 'sandboxed' mode which restricts app's access only to developers added in app configuration page. So after disabling this mode, I was able to generate access token for other users too.