Registration errors

Headerly stores DNR registration errors against the profile that produced them. The profile remains editable but does not have a working registered rule until the error is corrected.

Common causes include:

• unsupported or overly complex RE2 syntax;
• append applied to a request header outside Chrome's allowlist;
• an invalid redirect URL;
• an action with no valid required data;
• incompatible include and exclude conditions;
• a condition value unsupported by the current browser;
• Chrome rule or regular-expression quotas.

Correct the highlighted profile and let Headerly register it again. If the error remains after the profile is valid, run Reinitialize all rules in Settings.

Reinitialization removes and rebuilds Headerly rules. It does not change Chrome's API limits and cannot resolve conflicts caused by another extension.

For Regex errors, remove JavaScript /.../ delimiters and unsupported look-around or backreference syntax. See Regular expression filter.