I am having the same USB automount errors.
orangepipc -5.05 on Samsung Evo 32Gb w/ factory orange pi power supply
I can mount OK with sudo mount so that's not a problem.
I chased Policykit configuration for a day, no change.
Then I chased polkit-1 another day (apt-get install polkit-1), got it to finally say
$ pkaction --verbose --action-id org.freedesktop.udisks2.filesystem-mount
description: Mount a filesystem
message: Authentication is required to mount the filesystem
vendor: The udisks Project
vendor_url: http://udisks.freedesktop.org/
icon: drive-removable-media
implicit any: yes
implicit inactive: yes
implicit active: yes
But still No Authority to mount USB stick.
I then removed all the policy kit config files that I messed with and STILL get the above yes answers, but no authority.
Therefore armbian must not be using either form of polkit for authentication. Maybe its SELinux??
Edit: or not. not commands for SELinux installed.
I'll keep chasing it, but I'm running out of ideas.