Safari fails to load more and more sites daily.

Over the last week or so, more and more sites won't load most of the time. We're talking major sites like LinkedIn, Office Live, and others.

It turns out that the problem is Safari. The same sites load fine in Firefox, on the same system.

I don't have anything unusual running. No content blockers, firewall, anything.

Oh, and Safari is randomly losing all my log-ins. With increasing frequency, I find I'm logged out of all the sites I use regularly.

MS's live.com returned this on attempting to view E-mail:

Back Filled Errors: Unhandled Rejection: TypeError: Load failed:undefined|Unhandled Rejection: TypeError: Load failed:undefined|Unhandled Rejection: TypeError: StartupData:StartupData:Load failed:undefined|Unhandled Rejection: TypeError: StartupData:StartupData:Load failed:undefined|undefined:undefined|undefined:undefined|undefined:undefined|undefined:undefined

And often shows this: