More and more websites are unavailable because I get the 'your clock is ahead' message, with the https in the address bar with a red line through it. Have done all the clock updates (the date and time are, and always have been, correct) as advised by all the 'fixes' I can find on the internet, and have cleared my cache.
That typically occurs when an https certificate can't be updated due to using an out-of-date browser and/or operating system. So which browser are you using and which OS?
Hi Chris - Chrome and Vista. Have set it to all sorts of dates/times, and ticked the 'synchronise with internet time server', but it makes no difference!
Chrome is no longer supported on Vista (and hasn't been for the past 5 years), so that might be the cause of your problem. The 'developer level' web browser, Chromium, upon which its based doesn't either, so that would seem to rule out most alternative browsers (such as Slimjet, which I use). Firefox too has ended Vista support. It's beginning to look as if its time to bite the bullet and upgrade to either Windows 10 or Windows 11.
Just one thing to check though: Make sure that not only the time is set correctly on your computer but also that the actual time zone is too. If your computer thinks, for instance that it's now coming up to 2330 in New York, that will be seen as 0430 tomorrow morning by web servers, thus resulting in the error message that you're seeing.
I have set my clock time 4 hours further into the future and everything is still OK, but setting the date to 25/12/2021 resulted in 'Secure Connection Failed' for several sites and attempts to sync the clock with the internet then failed.
I haven't got a clue what an 'F11 reboot' is! (Or, at least I hadn't until I just googled it).
I now see that it's way of getting into System Recovery through the BIOS on certain makes of computer. I doubt that it would work but I suppose that it might be worth trying (after backing up all your data, of course). You could end up in a position though where you need to download and reinstall an out-of-date browser, simply because the latest versions are unlikely to run on any Vista computer.
I'm using Firefox ESR version 52.9.0 which seems fine for most purposes. I downloaded and installed it last year, but I'd need to remind myself where I found it, if you fancied giving it a try.