A brief notice from Broadsword Online Games on the Ultima Online website foretells of an outage on the Chesapeake shard:

We will be taking down Chesapeake at 2 pm ET today (8/17/2015) for a hardware update. The shard should not be down for more than 1 hour. Thank you for your patience.

So if for whatever reason you haven’t been able to log in to Chesapeake for the last fifteen minutes or so, that would be why.