issue certificate authority

Hi, can someone help me for this issue.

In my site using wireless connection, and radius server for authentication.

i have issue like this : The server “<Authentication server>” presented a valid certificate issued by “<CA name>”, but “<CA name>” is not configured as a valid trust anchor for this profile.

i try to folow this link : https://support.microsoft.com/id-id/kb/2518158 , but i don't know step by step for do that. can someone help me for clear this issue.

Thanks