Reference

https://community.fortinet.com/t5/FortiClient/Technical-Tip-How-to-check-and-enable-the-None-type-of/ta-p/374450

Situation

# Invitation裡面None反白選不到
Enable None option of Invitation of FortiClient.

Solution

[1]
Log in EMS server web.

[2]
System Settings > EMS Settings > Enforce User Verfication > Disable