Editing my response, as I can't see how to delete it. I had the same problem, but actually, I was connecting remotely to my mother's mac to install F-Secure SAFE. I found out that I cannot enable this remotely due to Apple's security measures. This makes good sense, actually. https://discussions.apple.com/thread/8087342
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Hello,
There was reply with suggestion:
https://community.f-secure.com/t5/F-Secure-SAFE/F-Secure-Safe-on-Mac-High-Sierra/m-p/101445/highlight/true#M18058
Where explained that MagicPrefs app is potential reason for inability to 'allow' (if such application is used).
Maybe you do able to look for such reply and back with feedback if your experience is not about such situation.
Thanks!
Editing my response, as I can't see how to delete it. I had the same problem, but actually, I was connecting remotely to my mother's mac to install F-Secure SAFE. I found out that I cannot enable this remotely due to Apple's security measures. This makes good sense, actually. https://discussions.apple.com/thread/8087342