Safari fails while other browsers work correctly

I usually use Safari and it usually works well for what I do... But now and then... I have a business website I visit maybe once a week or so... Until not too long ago, accessing that site worked OK using Safari... but then, one day, it put up a message like the following...

<h2>Our services aren't available right now</h2><p>We're working to restore all services as soon as possible</p>

And then a long line of letters and numbers beyond what I typed above... Seemed strange because it's sort of a major site... First time it did this I tried again a few times later, always with the same result... Then I tried another browser... Google Chrome Worked fine... then another browser... Firefox... Also worked fine...

Since then, these other two browsers always work ok (Chrome, Firefox), meaning it connects to the service I seek with no problem and Safari works but only occasionally... Most of the time it puts up the message above... Then it will surprise me and work fine!!!???

I reboot but not often... Otherwise, I don't like to empty caches or clear history when I don't know why that might help... Or what problems that can and does sometimes cause...

So why would two web browsers (Chrome and Firefox) always work on a modestly large business site where Safari fails with the above message more often than not... I would like to understand if possible!!!! thanks...