hello, when you type about:sync-log into the address bar and open the latest one or two error logs, can you copy their contents and put them into http://pastebin.mozilla.org/ or a similar service and paste a link here on the forum? this would be very helpful in assessing the problem. thank you!

Yes, thank you, here is the link to my log paste. I pasted the last two sync log files https://pastebin.mozilla.org/8838318

thank you, this appears to be a network related error - are you in a special environment, like a corporate network, where things like firewalls and network filtering might apply?

I'm on the road. Sometimes I'm not connected to the internet. When I am, I'm tethering from a hot spot or using a WIFI hotspot such as at a coffee shop or hotel. Is there any way to disable this message ribbon, especially when I'm not connected to a network? Thanks

My problem vanished after simple device name change - because I restored all settings from older PC (transfer to new PC with FEBE or MozBackup utility).

Simple I changed the PC name between brackets.

p.s. let Me know if it has helped... :-)