Why is Safari not opening websites on macOS Sequoia?

I have the same problem. I finally just made Chrome my default until Apple can fix the problem. Apple you should be shame. Fix the issue.

Same thing here. Apple support keeps passing me off to other people and everyone acts like this is a big surprise and I'm the only one...total nonsense. Hours have been wasted on this issue. They need to fix Sequoia 15.

For me, it mostly works, but when accessing web site with Digest authentication, it results in "400 Bad Request". It appears that Authorization header of such requests has a list of fields repeated multiple times, which is clearly a bug. Sometimes it creates a long line with fields repeated over and over. Some web-servers are not happy with that (nginx, for example). Before Sequoia upgrade, everything worked fine.

M1 MBP, lovely machine, but Safari and Signal no longer work after going to 15.0.1.

Safari is clean, no extensions and no browsing data. Web sites try to load, spin, and fail and then try to reload again. Signal looks like it can't connect. I have tried turning the Firewall completely off to no avail. Chrome works fine. Everything else works fine.

Building on the previous posting 👍

There are 3 Categories of Third Party Software / Services that are baffling to me.

Why some users insist on installing and using the below software. 

In no special orders 

Commercial VPNs 

They may not be what one believes they are doing for the computer and what they actually are doing behind the scenes 

https://gist.github.com/joepie91/5a9909939e6ce7d09e29

Third Party Security Software 

There are no known Windows-like Viruses in the wild that self replicate and affect macOS, because of the underling UNIX  Foundation and Permission Limitation. 

The Operating System resides in a Sealed and Read Only Volume that cannot be opened by the User nor by Third Party Applications.

The Only thing this Antivirus software is protecting is the Bank Account of the Developers and for zero return to the User aside from the problems this software creates.

Security. Built right in

Mac app security enhancements

The Built in Security  is all that is required to protect the computer.

Protecting against malware in macOS

Third Party Disk Cleaners / Optimizer 

Any Third Party Applications that will interfere with the normal operation of the OS,  is an invitation for disaster. 

Certain Applications maybe available on the Apple Apps Store - this only means the Developer is prepared to pay Apple a percentage on each sale. 

What the Application may do to the computer is up to the User to check this out before purchase

To put the Third Party Disk Cleaner / Optimizer in context and the damages it may have or has already done.

This type applications can or will Muck Up your User Account ( Home Folder ) of this machine.

It does not touch the Operating System itself unless you consider your User Account ( Home Folder ) as part of the Operating System

In which case, the Operating System is hosed

akire308 wrote:

Thanks for the explanation but I did not install any of the 3rd party softwares.

Also, I never experience any issues when I updated OS 16 & 17. Only happens after sequioia

iOS is for iPhones and iPads and iWatches

Download the Application Etrecheck  ( External Link ) directly from the Developer.

The Application is Not a " Silver Bullet "  and is  only a tool to examine the Hardware / Software used on this computer 

This is a Diagnostic Tool that makes no changes to the computer Hardware / Software used on this computer 

The application is free or paid from added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - >>>> using the Additional Text Icon ( 3rd Icon to last ) <<<<

Error 400 issue is not yet solved with 15.0.1...

:-(

You can inspect the request headers in Safari's network tab. I have the same issue, and I can see the Authorization header value is duplicated, making the request fail. The only way to solve it is to restart Safari. I hope Apple fixes it soon

Ever since upgrading to macOS Sequoia I'm having this problem too on my macBook Air M1, even on macOS 15.1. After some amount of time Safari stops functioning. Pages keep failing to load and the error message "This page was reloaded because a problem occurred" appears. It also sometimes causes the Finder to become sluggish/unresponsive. I already disabled all Safari extensions, but that didn't help. Activity Monitor doesn't show a huge increase in CPU or memory for Safari or any other process. I did once notice that both Rogue Amoeba SoundSource 5 and a Facetime process were red/not responding. Killing those didn't solve the Safari problem. Might be unrelated.

A macOS restart fixes the issue. Until it happens again after a while.

Here's a video showing the problem:

https://www.youtube.com/watch?v=HO1KJVyBSEk

The most likely cause is interference from 3rd party software, most likely some "security" app.

I also had the same issue of Safari not able to access the web after installing Sequoia. I disabled Hush - a cookie blocker - in Safari Settings and Safari worked perfectly again.

I have just upgraded to Sequoia 15.0.1 and it's really unstable. Not true it's fixed. Worked well for a couple of days, and instability just started this morning

I did the same until Chrome starts doing the same thing.