Unable to allow access in ARD client for specific users

I have ARD Admin 3.8 and manage over 100 computers at my company.

As per standard practice at my company, the setting for System Preferences > Sharing > Remote Management > Allow access for: is set to "Only these users:" The field is empty.

I've been trying to add an account through the Terminal. I SSH into a machine and run various commands, but they're not working:

These are the commands I've tried:

sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/k ickstart -activate -configure -access -on -users [username] -privs -all -restart -agent -menu

sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/k ickstart -configure -users [username] -access -on -privs -all

sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/k ickstart -activate -configure -users [username] -access -on -restart -agent -privs -all -allowAccessFor -specifiedUsers

None of them worked, I still can't authenticate to that machine with my ARD Admin.

Am I missing something? Is there something else I can try?

Thanks.