Why is one particular website being barred from accessing?
Under Mavericks 10.9.5, Safari 9.1.3 has been running pretty much just fine on my Mac for what seems several years now. But at some time in the last couple of months something's happened to Safari that now barrs me access to the shopping website of a well-known and well-respected UK highstreet dept store. This might have occurred following an unintentional deletion of the site from my bookmarked list of frequently-used websites. Now, no matter whether I insert this site's address into the browser's top-of-screen address field or I try to access the site via, say, a Google search page, all I get is a blank screen with a Safari message on it saying that Safari was unable to make a connection with that website's server. All other websites of other organisations and retailers appear untouched by this issue.
I'm currently at a loss as to why that website, and only that website, is prevented from connecting. It's not that the website is down or is permanently non-operational, because accessing it using a Windows laptop instead, via Edge, is no problem. Either my Safari's been corrupted in respect of this site, or possibly that site's no longer compatible with Safari 9.1.3. I've looked at all my configutration settings for Safari but can't see anything obvious that could cause this lockout. I've several times performed a safe-mode restart of the Mac but that hasn't cleared the condition.
I vaguely recall that some years ago something quite similar happened with the Amazon website. However, I can't remember how I fixed that in the end.
Anybody any ideas or suggestions for correcting this, preferably without me having to resort to doing a Time Machine restore? Should I try clearing out all current history, all browser cache, and all other bookmarked sites, and then forming the bookmarked ones again?
iMac (27-inch, Late 2013), OS X Mavericks (10.9.5)