nextcloudclient host not found

[Per olof Ljungmark]

FreeBSD12.0-STABLE and nextcloudclient-0.0.0.20190705_3

The client syncs fine for some time, then gives up with

QNetworkReply::HostNotFoundError "Host mynextcloudhost not found" 
QVariant(Invalid)

and it is impossible to restart the sync.

https://mynextcloudhost/status.php works well from a browser and the IP 
is resovable with drill and host and nslookup from Windows.

It appears from googling that this problem is not unique to me but I 
have failed to find a solution that works.

Anyone out there who found a solution to this?

Thanks!