You use the Safari on Mac? Also a user of Twitter (either the official app that was recently updated or the web, really)? Then you must have clicked on a shared link on the social network (with the shortener t.co), waited a few good seconds / minutes and came across an error message.

Well, you are not alone. In the Apple discussion forum there is a topic on the subject that was opened in October 2015! Everything indicates that the problem only affects HTTPS pages. The solution, at least for the time being: 1. will be reloading the page until it opens; 2. remove the https from the URL (if the short Twitter link has already taken you to the page in question); 3. open the link in another browser (Chrome, Firefox, etc.).
Seeking information on the subject, the The Verge found the following tweet:
@calebd @siracusa @siegel We have a Radar and a fix identified. It is lower level than WebKit.
– Timothy Hatcher (@xeenon) January 15, 2016
Timothy Hatcher (Apple's WebKit development manager) said that there is a Radar (problem report on Apple's tool) on the subject and that the fix has already been identified. According to him, the problem is at a lower level than WebKit (rendering engine used by Ma's browser).
Let's hope that Apple can fix everything in OS X 10.11.4 or, who knows, even before that.
CrashSafari

On a related note, someone with available time decided to play a trick on users of iGadgets/ Macs and created crashsafari. Upon entering it from an iOS device, the device restarts; Mac, the famous Giratria da Morte Beach Ball from OS X appears, the application freezes and in some cases you have to reset the machine to get everything back to normal.
According to 9to5Mac, the site itself is harmless and only works for those who visit. The problem responsible for the crash is a JavaScript code that makes the API request (application programming interface, or application programming interface) HTML5 History hundreds of times, in loop.
At this point in the championship, Apple is already in the know and should fix the problem in future versions of the system. For now, it is good to be careful not to click on links directing to the site (especially on services like Twitter, which use URL shorteners and “mask” things).