Safari kCFErrorDomainCFNetwork Error, Blank Page Fix

Do you see this Safari error message while browsing certain websites on your Mac. If you are getting a blank Safari page displaying the following error message, then this article is for you.

Safari can’t open the page. The error is: “The operation couldn’t be completed.(kCFErrorDomainCFNetwork error 303.)” (kCFErrorDomainCFNetwork:303)

Safari error cannot open page

I was in fact having this problem. Whenever I visited, Safari would not load the site and just displayed this error message. Here is how I resolved this message:

What is kCFErrorDomainCFNetwork error 303?

This is a parsing error. More specifically, the server is giving this error message because of encoding problems. It is probably due to the fact that Safari is saving too much data for that particular web site (for me:  You may want to also read a recent article on how you can reset Safari.

How to fix:

Please try each steps until your issue is resolved:

1-Let’s clean the problematic site’s cookies and data:

  • In the Safari app, click Safari and Preferences
  • Click the Privacy tab
  • Click the Manage Web Site Data button
  • A new window will open and you will see a list of websites that stored data.
  • Find the affected site (again this was for me), you can use the Search field to find easily.
  • Select the domain
  • And click the Remove button
  • And click done.

Now try again opening the web site. Do you experience the same problem? If so, continue to the next step.

2Start your Mac in Safe Mode.  This is an easy process. Here is how:

Safe Mode will start your Mac in a basic state with only the original software that came with it. Some of the features of your Mac will not be available in Safe Mode. Here is how:

  • Turn off your Mac
  • Turn on your Mac and immediately after tuning on, press and hold the Shift key
  • Keep holding the Shift key until you see the login window
  • Release the key and login
  • Now your computer is in Safe Mode
  • Open Safari and test to see if this problem occurs. If not, exit Safe mode.
  • To exit Safe Mode, restart your computer normally without pressing the Shift key. You could not start your Mac normally, read this article?

Did the tips above help you? Please leave a comment.

Dr. Serhat Kurt worked as a Senior Technology Director. He holds a doctoral degree (or doctorate) from the University of Illinois at Urbana / Champaign and a master’s degree from Purdue University. Here is his LinkedIn profile.

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15 thoughts on “Safari kCFErrorDomainCFNetwork Error, Blank Page Fix”

  1. I am having this problem with the images on the local html after upgrade to Big Sur. Disaster. Apple is stealing our time resolving things, which were just fine before.

  2. Got there in the end! very useful tip. At first I took your example too literally (‘’) as it sounded like the kind of background site that stored useless data and bloated my computer. I did happen to have ‘’ listed so deleted that but it didn’t clear the problem. The thing to know here is that whatever site you could not reach (whatever site gave you the ‘KCFErrordomain’ message) – THAT’s the one to delete from the ‘manage data’ list.

  3. My website worked fine in safe mode but will not work regularly. I keep getting This Connection is not private and won’t move past this how do I fix this

  4. These steps worked for me, but a caveat. I used the search function to find the affected site, the digital loans section of my library website, and found one entry that looked like the culprit. What I did not realize was that there were two more sites I needed to clear, that didn’t show up with my search. I went back and searched for several key words and found two more sites to clear. Once I found those and removed them, problem solved. So if at first you don’t succeed, look through your whole list of websites if need be, or search on several key words.


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