It's up for me right now.  Was up last night too.

The server has NOT been down over the weekend - I have played a number of games with people. You need to check you have all the ports listed in your user.setting file open.

Or here's a radical idea - try turning off your firewall and see if it works. That is how I worked out the problem my end when I upgraded to 1.11 from 1.05. Turned out I needed to open port 7000 on my modem firewall....

I've opened port 7000, turned off all firewall & antivirus & still no ICO...

And what version of the game are you using? (Bottom right of the screen). You need to be on 1.12

Fully updated to 1.12.

Worked fine for weeks but suddenly nothing.

Its works for many other people, so going on all my years of experience... I would think something on your end MUST have changed - things like this don't just stop working for no reason, and if the something that changed was on the server end, everyone would be having issues... Doesn't help you fix your issue though....

Could it also be a router between him and the ICO server?

I do use a router/modem combo, but I've shut down its internal firewall & forwarded all ports used by Sins & ICO.

Look into double NAT - The Monk used to help people with this issue.

plug directly into the modem and see if that works...if so, then it's your router.

have you tried a restart of all the components?

My comp is directly hooked to to my modem/router via ethernet. My kids both have a wireless connection for their's.

I've reset the modem & my ethernet adapter, turned off ALL protection apps to test & even had a line test done.

Try this

1) Open Task Manager and get the Sins process ID (you may need to add the column as it often isn't on by default)

2) get a comand window and have "netstat -aon | more"  ready to go (the  pipe to more allows you to see a screen at a time)

3) Alt-tab back to Sins and select connect to ICO

4) Quickly rush back to the cmd promt and hit enter. Look for the process ID of Sins in the list. You may need to repeat this a few times if timing is off

When I log into ICO, I get the following mixed into my response from the netstat

 TCP    192.168.1.1:52935      38.98.152.153:7000     ESTABLISHED     11656

192.168.1.1 is my internal IP address (i.e. inside my network)

11656 is the PID Sins is running under currently (obviously changes)

as you can see, I am connecting to IP address 38.98.152.153 on port 7000 and the connection is established

5) Make sure port 7000 is open on any firewall between you and internet - this includes windows and router/modem

6) Do a tracert (trace route) to 38.98.152.153

Incidently, if you ping ico.stardock.com you will see that it resolves to 38.98.152.153

Good luck - if this doesn't fix it, it is something else and support will have to help you