In-house email direct to Junk Folder

I have experienced repeatedly, though infrequently, that email from people in my company to me are moved to the junk mail folder. When I try to mark it as Not Junk, I get a message that mail from people in my company will never be marked as Junk. As I was looking at the Junk Email folder, that is ironic. I have a screenshot but see no way to attach that to this message.