I am unable to open JotForm in Safari browser on Mac. It shows fatal error message.

Mac Safari (latest version) doesn't open jotform but gives an error:

Fatal error: Uncaught Error: Class 'Configs' not found in /www/v3/live/lib/init.php:120 Stack trace: #0 /www/v3/live/index.php(4): include_once() #1 {main} thrown in /www/v3/live/lib/init.php on line 120

Bert

I'm sorry for the trouble caused to you. 

I did try to login to my jotform account (through browserstack) using Safari browser version 10.1 on Mac OS X, Sierra  and I am unable to replicate the issue you are having. Please check the screenshot below:

Do you get this error message when you try to login to your account or when you access your form with its direct URL?

Do get back to on this and we will report it to our backend team. I would also suggest you to please share a screenshot of the issue and we will take a look. The following guide should help you how to upload image in forum post:  https://www.jotform.com/help/438-How-to-Post-Screenshots-to-Our-Support-Forum

We will wait for your response.

It happened the whole morning, just using the jotformpro url.

I can't reproduce it either now. So issue can be closed.