Access to website / citrix

Hi

I cannot access a website that allows me access to a work network - so the website is http://access.[company].co.uk/Citrix - I keep getting a 'server not responding' error via Safari and Firefox. However, it all worked fine yesterday, and nothing has changed at my end and IT support are insisting nothing has changed at their end. I can access the website from a PC. The website detects citrix receiver and then launches this, although I'm not even getting to that point - website doesn't even load.

Any ideas?

Thanks