Hi mike_1947,
We appreciate you reaching out to us. We understand that Facebook is not working as expected if you use Safari.
We’d like to gather additional details that may help us be in a better position to assist you.
Have you had the chance to try the steps in the article below?
If Safari on Mac doesn't open a webpage or isn’t working as expected - Apple Support
If yes, let’s check if the issue persists when signed in on a different user account.
Performing this step can help in isolating the issue
The article below can help if you do not have any other user account to test with.
Set up users, guests, and groups on Mac
If you are experiencing the issue when signed in on a different user account, please check if the issue persists while on safe mode.
Safe mode prevents your Mac from loading certain software as it starts up which can help identify issues caused by software extensions.
Performing this step may help resolve the issue, or further isolate the issue.
Below is an article to help guide you through the process.
How to use safe mode on your Mac
Take care!