Safari fails to open any site with many errors, e.g. WebKitErrorDomain:300

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Safari fails to open any site with many errors, e.g. WebKitErrorDomain:300

After upgrade to Monterey, Safari stopped opening any website.

When I try to open google.com it says:

400. That’s an error.
Your client has issued a malformed or illegal request. That’s all we know.

Sometimes it returns:

Safari can’t open the page “https://www.gazeta.pl/”. The error is: “WebKit encountered an internal error” (WebKitErrorDomain:300)

or

Safari can’t open the page. The error is: “The operation couldn’t be completed. (kNWErrorDomainPOSIX error 100 - Protocol error)” (kNWErrorDomainPOSIX:100).

I tried clearing preferences and caches in Library folder, changing back and forth all Safari options, restarting Safari and Mac multiple times. Nothing helps.

Please help!

Everything works just fine in Chrome.

Thanks,

Mariusz

MacBook Pro 15″, macOS 12.0

Posted on Oct 28, 2021 12:25 AM

Reply

Answer 1

Chris_C1

Community Specialist

Oct 29, 2021 6:21 AM in response to mariusz101

Hello mariusz101,

Welcome to Apple Support Communities. We understand the importance of having Safari working as expected on your Mac, and we'd like to help.

We have some great steps available that will possibly resolve the issue. Please complete all the steps listed here:

If Safari on Mac doesn't open a webpage or isn’t working as expected

If the issue persists, let's try to test in safe mode, and in another user account. here's how:

Start up your Mac in safe mode

Set up users, guests, and groups on Mac

Let us know the results. Kind regards.

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Answer 2

Jeff_W.

Community Specialist

Nov 2, 2021 6:07 AM in response to mariusz101

Hello mariusz101,

Thanks for getting back to us with those additional details. It looks like you're having issues using Safari on your Mac after updating to macOS Monterey. Let's continue working on this together.

When an issue doesn’t happen in a new test user, that means a setting or a file in your original account might be causing issues. We can continue to look into why your original user account had these issues.

Next, we'd like to try removing other add-ons that can affect Safari by following these steps:

Quit Safari
Open the Library folder (Finder > Go > Library)
Open the Library folder in the user's home folder (Finder > Go(while pressing the "Options" button) > Library)
Open each folder, if present, and move any files within to a subfolder:

Internet Plug-Ins

Don't remove Default Browser.plugin, nslQTScriptablePlugin.xpt, Quartz Composer.webplugin, or QuickTime Plugin.plugin, if present.

Input Methods

InputManagers

ScriptingAdditions

If removing the files from these folders resolves the issue, quit Safari again and gradually put the files back to attempt to isolate the file at fault.

If the behavior persists or you run into any trouble, please reach out again. Cheers!

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