lightroom won't sync after moving catalog to new hard drive

Hello,

I recently moved my lightroom catalog and photos to a new external hard drive because I used up the space on my old external hard drive. Now when I try to sync photos from my phone I keep getting a message saying:

This appears to be a duplicate or automatically created backup of your catalog.  As it may not be current, sync has been disabled for this catalog.  Please open your production catalog to resume sync.

To make this your sync catalog,

go to: Lightroom > Preferences > Lightroom mobile

and click the “Delete All Data” button to start fresh.

What does this mean? Is there a way to let Lightroom mobile know the new location of my catalog without having to "delete all data"?

Thanks,

Ben