No, there is no problems with uk4. Other streams on that server are working fine at the moment. We can see that your server is currently switched on, it just does not have any source connected at present.
What encoder are you trying to connect with? Are you getting any error messages?
something to beware of (as I got a call from the local community station when this happened) - a fault with your broadband (intermittent disconnection, can be caused by weather or faults at the ISP) will appear to your streaming software as "cannot connect to server" until the Internet connection is restored. if your network hardware is not within plain sight of your streaming PC (to the point you can actually watch the "blinkenlights") its not immediately obvious where the fault lies. Although a broadband circuit which isn't completely defective usually restores this can take a minute or more which is of course a long time in broadcasting!
Although the public internet is way more reliable than it once was in the UK; it actually has no regulated service level agreement unlike voice calls (for 999/112). No European country currently has a guaranteed service level for broadband - its viewed as "best efforts".
Of course a company which advertises a service and cannot deliver it can get trouble with the Communications Ministry; but the priority is on keeping voice calls working. The usual reliablilty level for UK business circuits when translated into real figures gives wriggle room of 3 whole days without service and from experience I've found that to be the case no matter what provided you use.
The BBC and ILR use very expensive dedicated circuits to get sound from one place to another called Facility Lines which I think only Arqiva now provide; British Telecom may have walked away from the market as even with the premium price it wasn't profitable for them.
The last lot were based around ISDN so you (if it wasn't a 24x7 link and priced as such) would have incurred a cost of 2 x national phone calls to wherever your TX site was for all the time you were broadcasting; on top of other bandwidth costs to get it to the internet.
If you need 100% reliability you could possibly use a JFMG link as a backup; or the new fangled IP-over everything boxes which are basically a giant one way VOIP telephone. those aren't cheap either and might not even provide the resilience you expect unless you shell out for both fixed and mobile broadband (even then theres a potential single point of failure at your local Telephone Exchange).
I've had a look at your very interesting setup (my day job is in ICT engineering for healthcare) and although its a very smart idea to use a service like this to feed two hospitals in geographically separate sites it will always be dependent on the public internet working well.
What particularly interests me is that I work in a lot of seniors homes and I was wondering why there aren't more radio stations for the older European generations; many of whom grew up with British Relay / PTT cable radio as well as offshore pirates..
harsh facts with all this online/cloud stuff are that we are increasingly trading more features for less resilience unless you invest more in backup infrastructure. Depending on how far apart the sites are and what other resources you have available there are ways you could guard against any sort of network failure with your setup but they would need close liaison between your station and the clever folk who set up the patients terminal equipment; and more investment on the stations part.
PS: in the interests of full disclosure (as some may have noticed my user title change) I help out moderating this forum voluntarily - the only other compensation I get from internet-radio.com is the use of one of the streams; although I support what they do I am not acting in a PR/damage limitation role - as an engineer I have an ethos of honestly stating if something is flawed/defective with a view to it being improved. I can confirm that if any big problems do occur with these servers (I set up similar ones for processing business critical data at work) all sorts of alarms trigger and those who run them will be warned 24/7 of the issues..