奥吉尔，

根据您的描述，人员选择器仅对某些用户有效，而对某些用户无效. 

工作的用户和签发的用户是否来自同一域?

此外，您可以创建，建议您在Office 365论坛中创建一个新线程:

http://answers.microsoft.com/en-us

我们建议适当发布的原因是，您将获得最合格的受访者群体，定期阅读论坛的其他合作伙伴可以分享他们的知识或从您与我们的互动中学习. 感谢您的理解.

***的问候

陈丽莎

Hi Orgil, 

From your description, people picker works for some users while not works for some users. 

Does the worked users and issued users come from the same domain?

Besides, you can create I suggest you creating a new thread in office 365 forum:

http://answers.microsoft.com/en-us

The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thanks for your understanding.

Best Regards, 

Lisa Chen