"Offline. Changes won't appear on your other devices until 1Password reconnects."

I’m posting this here as a service to the stymied. My 1Password, both on mobile and desktop, was complaining about being “offline,” despite my not actually being offline.

The error message on the desktop, accompanied by a red cloud icon in the app’s toolbar with a slash through it, looked like this:

I was confounded.

I uninstalled and reinstalled, checked my network connection, restarted my computer: nothing helped.

With the aid of 1Password support, to which I sent a diagnostics log, I learned that the error was a result of a 1Password Business account to which I no longer had access still being “signed in”:

Thanks for sending that diagnostics report through to me from 1Password on your Mac and apologies for the confusion as to why 1Password is reporting itself as offline here. After taking a look at the report, it looks like you have a suspended 1Password Business account signed in to the app on your Mac which is why 1Password is reporting itself as offline.

Sure enought that was it: I signed out of the offending account, and suddently I was “back online.”