Ancestry.com has announced that it will undergo scheduled maintenance tomorrow, Wednesday 25 August, from 12am EDT.
Whether this impacts access to Ancestry.co.uk or any of the other 'territory' websites, I don't know for sure, but it's being flagged up on the UK site, too, so it probably will.So, if you find some portions of the website are unavailable in the morning (and possibly for some time), you'll know what's likely to be causing the problem.