Clear cache and cookies

Empty Caches (Safari menu > Preferences > Privacy > Remove all website data. (This will also remove history if you do not want to remove History open Safari Preferences > Advanced and check mark “Show Develop Menu” then choose “Empty Caches” from Develop Menu ).

Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items.  Quit/reopen Safari and test. You can also try try Safari/Clear History…. The down side is it clears all cookies. Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. The following won't work in OS Mojave. Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J.  When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder.  Select Library/Caches/com.apple.Safari/Cache.db and move it to the trash.

Or you can manually delete the cookies by going to Safari/Preferences/Privacy/Manage Website Data.

If you attempt to clear cache and cookies with a website still loaded in the browser, neither cache or cookies will remain empty.

Instead, press and hold the shift key when launching Safari. Now do the following to clear all cookies and cache:

1. Safari Preferences : Advanced : [√] Show Develop menu in menu bar
   1. Press option+command+e to clear browser cache
2. Clear all cookies (and history)
   1. Safari menu : Clear History… : all history : Clear History

Quit Safari and relaunch normally.