Thank you for your message.
There were neither any downtimes of our servers, nor any changes to the program. Remote Utilities simply doesn't have any auto-update capabilities, so even if we released a new update that wouldn't affect your installations.
We will check information about black listing. However, our servers always have a static IP address - for example, our primary server as well as secondary servers didn't change its IP address for years, and the server itself is the only application/service that is running there. So it would be rather strange if that IP address were added to a black list - there's simply no email or web service there to host anything malicious (even if we hypothesize so :) ).
It would also help looking at your Host log files. Could you please submit a ticket and attach your Host logs to the ticket. Perhaps, the Host can't connect to the intermediaries because of a DNS issue or something else. But we need to take a look at the logs to be sure.