safari 17.3.1 compatibility with websites

You are looking in the wrong place. Leave the Settings menu. Look at the very top of the Safari screen, next to Bookmarks tab, and see the Develop tab. That’s where you will find the Empty Caches option. You can also empty caches with the shortcut Option-Command-E

Yes it does, near the bottom of the Develop menu. “Empty Caches” third option from the bottom of the Develop menu.

1. Have you updated Safari to the current version?
2. Have you updated your macOS to the current version?
3. What macOS are you running? Sonoma, Ventura, Monterey, what?

Your issues are most likely to do with cookies, caches, or both.

Safari->Settings->Privacy->Manage website data->Remove All to clear all cookies and website data.

Safari->Settings->Advanced-> check Show features for website developers. A Develop menu now appears the Safari top menu bar. Select Empty Caches. Close and relaunch Safari and see if those websites don’t suddenly start working again. Don’t mess with anything else unless you are fully cognizant of those options. Otherwise you could brick browsing altogether.

And of course Safari is now at version 17.4.1 so it would be prudent to update your Safari to the current version first of all.

I have been using Safari to sign into Ancestry for 16 years with no problem until 2 days ago. I contacted Ancestry and was told I probably had a corrupt web browser. I search the web and found information that Ancestry did not preform well with Safari. I have Google Chrome on my MacBook Pro laptop 13" v 14.5. I did use them as my browser for a short time. I did not find them to be user friendly and overall did not like their system. I signed into Ancestry using Chrome as my browser and Ancestry's screen was the same as signing into Safari. I will use Chrome to sign into Ancestry, only because I have no choice. I will continue using goole on Safari for surfing the web and for emails.

That’s utter nonsense. I continue to use Safari to access Ancestry.com. What ever you read about Safari and Ancestry not being compatible is completely wrong and probably written by someone who doesn't know what they are talking about.

Read and perform the suggestions above to clear caches, delete Ancestry cookies and website data.