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kCFErrorDomainCFNetwork Error 303 Mac – Fix It Guide

What Is kCFErrorDomainCFNetwork Error 303?

kCFErrorDomainCFNetwork Error 303 is a network error for Mac. This particular error is concerning the Safari web browser, where it may fail to open a certain website. Victims who have reported it have also noticed this problem on iPhone and iPad as well.

Read this article to find out more information concerning the kCFErrorDomainCFNetwork Error 303 and what you can do to fix it.

kCFErrorDomainCFNetwork Error 303 Mac

kCFErrorDomainCFNetwork Error 303 Summary

Name kCFErrorDomainCFNetwork Error 303
Type Network Error / Browser Runtime Error
Short Description May cause a lot of problems on Safari, concerning opening websites.
Symptoms When you open a certain website, the message “kCFErrorDomainCFNetwork Error 303” appears.
Program Safari on macOS
Fix Tool Try this fix to repair your Mac from errors and optimise system performance:



kCFErrorDomainCFNetwork Error 303 – What Are Its Symptoms

kCFErrorDomainCFNetwork Error 303 is a typical network or a runtime error. Other errors similar to it may also include -2100F, -2003F and 1008F.

kCFErrorDomainCFNetwork Error 303 is the type of problem, which has been noticed on Apple Discussions forums. Victims had the following to say concerning this error:

I keep getting the above error on a specific website. I clear the affected cookie and it allows me to visit the site once and then the error comes up again.
I have spoken to the owner of the site and they keep saying to use another browser but I am running my business all on apple kit and want to keep it to Safari. I get the issue on my iPhone and iPad as well.
The link works without any issues in Chrome on all devices.
Appreciate any help

If you see this kCFErrorDomainCFNetwork Error 303, you may also experience the following symptoms:

  • Internet speed starts slowing down.
  • Your device may behave erratically.
  • Some of your other apps may stop functioning.

kCFErrorDomainCFNetwork Error 303 is the type of error, that may be caused by several different reasons. It may be due to faulty code or even malware running on your Mac.

kCFErrorDomainCFNetwork Error 303 – How to Fix It?

According to experts on community forums, the following fixes were able to fix the problems, related to this error.

  1. Open Preferences in Safari.
  2. From there, go to Privacy.
  3. Search for the website that you are trying to open.
  4. Click on “Remove” and the problem should be fixed.

If this fix does not help, you can also try the following repairs.

Step 1: Close any apps or programs that may be in conflict.

When you get errors, like this one, often conflicting apps may be the case. Below, you can find the solutions for closing conflicting apps for Windows and macOS:

For macOS:

Go to Activity Monitor, mark any processes you believe are suspicious and close them by clicking the “X” button on top left above them.

After you have done this fix, you should observe if this error will show up again if you start and stop a specific process.

Step 2: Update and Re-install Any Software You Believe is Problematic.

For macOS:

Go to Applications and drag the icon of your program to Bin to uninstall it. For macOS, you can go to your AppStore and click on the “Updates” tab to check if any applications are out of date.

Step 3: Install the latest updates of your OS.

For macOS:

Go to System Preferences – Software Update and check for a newer macOS version. You will see a button to install it and Upgrade if its available.

Step 4: Scan your computer for errors and optimise it automatically.

If you have tried most of the fixes, but you keep getting error messages, then the best advice to go for is to make sure and check your computer for:

You can do all of this by running an automatic scan of your computer using a professional anti-malware software. Such an advanced tool is created by cybersecurity and tech experts and is guaranteed to help detect and delete any malicious files and whatever may be causing errors and optimise your computer to make it fast again:



Spy Hunter scanner will only detect the problem. If you want the issue to be automatically removed, you need to purchase the full version of the anti-malware tool.Find Out More About SpyHunter Anti-Malware Tool / How to Uninstall SpyHunter

Mac Errors – Frequently Asked Questions

What are Mac Errors?

Mac errors are faulty problems of macOS. They are different types, affecting various programs running on your Mac.

Since macOS is frequently updated, it is easier to fix such errors, due to the way this operating system is constructed.

What Do Mac Error Codes Mean?

Error Codes on Mac are how your macOS explains the different types of problems that can occur on it. The number of the Mac Error code pops up on your screen, and it shows you the error with some explanatory text to help you fix it.

These error codes exist for both small and bigger problems, and in some cases, they can mean that there is a significant issue with your device.

Why Do I See Errors On My Mac?

The reasons may vary. These can be due to a badly written code, faulty software, external app modifying your app, incompatibility, problems with the resources required to run the app, and even a Mac malware infection.

What Types of Mac Errors Exist?

Just like with Windows devices, there are some general error types with Mac as well, including:

  • Runtime Errors – when you execute a program and it fails due to badly written code, incompatibility with the program and web servers or other problems, like malware.
  • Logic Errors – something in the logic makes the program fail to return results.
  • Arithmetic Errors – a type of logic error, which involves miscalculation due to an erroneous configuration or code that does not fit the same logic as the system reads it.
  • Resource Errors – when your device does not meet the resources required to run a program or if the program is coded faulty, so it requires more resources than necessary.
  • Interface Errors – when there is a difference between what an app is meant to do and what it actually does.
  • Compilation Errors – when the compiler of a software fails to turn complicated code into a simple language, understandable by your Mac.

Which are The Most Common Mac Errors?

According to different sources and online forums, the most commonly encountered errors on Mac carry the following codes:

  • Error Code 36 – when Finder fails to read or write a file on your Mac.
  • Error Code 41 – caused by malware, outdated software or corrupted files and directories.
  • Error Code 50 – when you fail to copy and paste a file onto another drive, like USB or an external SSD or HDD.
  • Error Code 2003F – it shows up when you try reinstalling your macOS in Recovery Mode. Possible causes include bad sectors in the hard disk, malware, etc.

What to Do If I See a Mac Error?

If you see an error on your Mac, your first job is to check the meaning of it. Then, you can see reputable forums, like Apple Discussions or SensorsTechForum in order to find different types of fixes for the problem.

How to Stop Getting Mac Errors?

You cannot. As long as there are people writing the code, there will always be the human error factor. However, there are several measures that you can take in order to significantly reduce the chance of getting a Mac Error:

  1. Check and update your Mac and your Apps (if possible) to the latest version on a daily basis.
  2. Install a relevant and reputable anti-malware for Mac.
  3. Install an optimizer for your Mac, which will keep all your apps updated, remove junk software, and improve your Mac’s health.
  4. Only install apps from trusted sources.

Ventsislav Krastev

Ventsislav is a cybersecurity expert at SensorsTechForum since 2015. He has been researching, covering, helping victims with the latest malware infections plus testing and reviewing software and the newest tech developments. Having graduated Marketing as well, Ventsislav also has passion for learning new shifts and innovations in cybersecurity that become game changers. After studying Value Chain Management, Network Administration and Computer Administration of System Applications, he found his true calling within the cybersecrurity industry and is a strong believer in the education of every user towards online safety and security.

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