I've never had such an error, and haven't yet moved from SL6 to SL7. 
But out of curiosity I googled

error getting authority error initializing authority could not connect

There are several pages with explanations and suggestions, such as trying 
'journalctl -xb' to see what went wrong and/or adding the option nofail to 
the failing mount point or all the mount points that are not required at 
boot time.

Steven Yellin

On Mon, 20 Feb 2017, MAH Maccallum wrote:

> My laptop is set up to dual boot Windows 10 and SL7. I had
> backed up all my Linux files and made a Windows 7 style
> backup of the Windows partition. Then I accidentally exited
> Windows by 'restart' rather than 'shut down'. The result is I
> cannot reboot the Linux. I get my usual grub menu but trying
> to start Linux from it gets (after a couple of warnings which are the
> same I had before):
> Welcome to emergency mode!.....
> and trying either of the suggested 'systemctl reboot' or
> 'systemctl default' leads to a message
> Error getting authority: Error initialising authority: Could not connect: No such file or directory (g-io-error quark,1)
>
> I can boot from a Live USB and mount the linux partitions. I am pretty
> confident therefore that no data has been lost from them.
>
> Is there a way to recover short of wiping the disk and reinstalling
> from the beginning?
>
> Malcolm MacCallum
>