Initially after I updated Safari, I could not access any of my bank or email webpages. Kept getting an error message that something was wrong and page could not be loaded. Tried a few things to get it back to normal and fianlly called Apple Support. He said originally Safari15 was not going to be available to Catalina, which I am using. He provided a link to some sort of patch which I installed and everything returned to normal. No more error messages on my bank or email pages.