Safari blank page

Running Safari 14.1.2 on Mojave 10.14.6 on a Mid 2010 Mac Pro.

So recently I discovered that I am unable to login in to my web domain host site. As soon as I log in, it gives me a blank page. They have a message about cookies needing to be enabled and all and I have allowed total access to the site, but it still won't load anything. So basically the main site loads but when it attempts to switch to the secure site at login, that page is completely blank.

I downloaded Firefox and it was able to load... although it was extremely slow. It clearly was using pop-up windows during the login process which I could not see under Safari. I tried everything I could to allow cookies et al but nothing under Safari. I used the default Firefox settings as initially generated upon launch and it worked... albeit very slowly.

Is Safari depreciated too much for the website or is it the website that has poor coding? Only every ran into this situation on this site and clearly it's only blocking stuff once attempting to go via secure mode.

Any thoughts?

Website is readyhosting.com, but only upon attempting to login to their secure site.