I picked out the actual URL from one of those messages and entered it into a browser, and got the message
"Unable to connect
Firefox can't establish a connection to the server at www.*********** (edited out)
The site could be temporarily unavailable or too busy. Try again in a few
moments.
If you are unable to load any pages, check your computer's network
connection.
If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web."