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Error messages & crashes
Error messages & crashes
Updated over a week ago

In most cases, 1Blocker works seamlessly, exchanging data with Safari with no issues. However, our app and the browser can throw several types of errors if they cannot handle the data processing.

This short overview will give you the steps to follow if you come across an error message or a crash. Also, we will describe the most typical error types.

How to report?

Some error messages contain a brief description telling you what exactly is wrong. It may help solve these issues without our assistance. However, if they are too vague, feel free to contact us directly. We will do our best to put 1Blocker back on track!

Here's how you can contact us, report any issues, or share your feedback:

  • using the "Report" section available in 1Blocker Safari extension;

  • using the "Send Feedback" button, which you can find in the Settings tab or 1Blocker Safari extension;

  • via our email - [email protected];

  • via Twitter.

Please, opt for built-in report and feedback buttons, if possible. It's the fastest and most convenient way of reporting sites because such messages automatically include page URL, device, and 1Blocker version.

What information should be included?

If there is an error message popping up, or the app is occasionally crashing, and you are going to report it, please, consider including the following information:

  • describe as detailed as possible the steps to reproduce the issue;

  • mention the buttons you've pressed, categories affected, the rules you've edited, or the websites you've visited just before the problem occurred;

  • feel free to attach any screenshots as they are usually helpful;

Some common error messages



WKErrorDomain error message usually appears while working with custom rules, hiding web elements, or syncing rules with Safari. It is not a 1Blocker message, but the browser's one. It appears when Safari cannot parse the rules properly. In most cases, it simply means that one of the custom rules contains a syntax error, so it is crucial to determine which rule triggers it.

How to troubleshoot WKErrorDomain?

First of all, please, try disabling a couple of language-specific categories listed under the "Regional" section. Perhaps three or four regional categories will be enough for your everyday browsing. There are a lot of regional categories and enabling too many of them causes this error, because in this case, the total number of rules may surpass Apple’s limit of entries per extension.

If the issue persists though, you will need to find the entry that breaks the rule processing, and when you are ready, you can send the screenshot or the rule itself to us so that we will check and fix it.

Start turning off all categories and groups of rules one by one in the "Custom" section, starting from the categories containing the most recent changes. As soon as you turn off the category that contains the problematic rule, the error won't show up anymore.

It is an important intermediate result because now you know which category contains the problematic rule. It's time to dive a bit deeper. Now you need to re-enable the category and check all the rules inside it by turning them off one by one, just the same way you've done with categories.

When the broken rule is detected and the message disappears, you can either remove it, try to fix it yourself, or contact us, and we will help.


If you see this message either in the app or the Visual Editor while creating a custom rule, it probably means that Safari cannot process the rule. It is worth making sure that our extensions and the category responsible for this particular rule are enabled both in 1Blocker and Safari settings.

If the error persists, please, try to troubleshoot it by following the steps from the paragraph about the WKErrorDomain issue.

Failed to modify some records

The error appears in rare cases, and this is how the system behaves when it cannot process or store information in iCloud. It can usually be fixed by toggling either iCloud Drive's or 1Blocker's bubble in the iCloud settings: iOS Settings > [Your Apple ID] > iCloud.

CKErrorDomain error 3

This message is coming from the service that 1Blocker uses to sync data with iCloud. If you are getting this message, especially while trying to contact us via the app, please, make sure that you are on Wi-Fi or enable Mobile Data in iOS Settings > 1Blocker.

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