Can't connect to Nabu Casa Remote Control after HA rebuild

Running HA on an NUC. My SSD failed, so I reinstalled HA from scratch and restored a backup from a network server.

My Nabu Casa account says I’m connected, but the Remote Control panel says:
There was an error generating the certificate, check your logs.

which shows:
Logger: hass_nabucasa.cloud_api
Source: components/cloud/google_config.py:380
First occurred: 10:45:23 (1 occurrences)
Last logged: 10:45:23

Fetched https://remotestate.nabucasa.com/request_sync (500)

I’ve searched here for a solution. I’ve made the .storage and .cloud files visible in the File Editor. I’ve deleted the cloud folder in .storage and tried to delete the .cloud folder but get:
{Errno 39} Directory not empty.

So, I renamed .cloud to ###.cloud and restarted.

After restart, I can see HA has recreated both cloud folders. After signing in to Nabu Casa, I still get the certificate error.

At my wit’s end. Can anyone shed light on this?

Many, many thanks.