Suddenly Not Syncing

New DTP and DTPTG client, here.
In the past couple of days my sync database stopped synching with my device. Here’s my set up:

Two databases on my Mac Desktop, 1 is everything (8gigs!) and the other is my To Go db, which is called “Current Reading”. This second db (almost 1 gig, plenty of space on the iCloud) is the one that I have previously connected to the iCloud to sync my current reading list among my Desktop and my iPad.

In the past week, PDFs that I upload to “Current Reading” haven’t been showing up on the iPad.
Unfortunately, I did have to reboot my computer, perhaps this is related?

Thinking I could re-set up the sync, I uninstalled and reintalled DTGTG from my iPad/Apple Store, but now I don’t have an encryption key with which to continue.
Please help.

I don’t want to delete “Current Reading” and lose highlights, notes, etc.
Not sure how to best proceed.

Are you able to successfully synchronize the sync store (see contextual menu in Preferences > Sync)?

What’s reported in DEVONthink’s Window > Log?

From DevonThink Log: “Invalid Encryption Key”

I don’t understand… is this a contextual menu on my Desktop? From DTP menu or Apple’s IOS Pref’s?

Did you add / remove / or modify the encryption key for the sync location?

Does the Mac have the master databases?

Yes, the Mac Desktop (10.13.4) has all the master databases.
(I recently had to wipe the computer and reboot from a back-up.)

No, I did not add / remove / or modify the encryption key for the sync location.

Should I open a support ticket?

Sure. Hold the Option key and choose Help > Report Bug in DEVONthink. Thanks