Error message: PHP Fatal error: Uncaught TypeError

Problem

At least one Script Blocker is active and the error message appears on some pages:

PHP Fatal error: Uncaught TypeError: 
BorlabsCookieSystemWordPressFrontendDriverOutputBufferManager::getBuffer(): 
Return value must be of type string, null returned in 
/var/www/html/wp-content/plugins/borlabs-cookie/classes/Cookie/System/WordPressFrontendDriver/OutputBufferManager.php

Cause

Cause A

Check under Borlabs Cookie > System > Logs whether there is a Critical error whose message starts with "Your inline CSS appears to be excessively".

Cause B

There could be an extremely large script tag on your website that exceeds the backtrace limit of regular expressions in PHP. This limit is 1,000,000 by default.

Cause C

A plugin or the theme used has an error when handling buffers. This causes our buffer to be disturbed, which in turn means that our plugin does not receive the expected data.

Solution

Solution for cause A

You have too much inline CSS, so you should check your plugins that can perform CSS optimizations. Too much CSS is inserted directly into the respective page, although this amount of CSS should be in a separate file.

Solution for cause B

Set the backtrace limit high via wp-config.php, e.g. to 5,000,000:

ini_set('pcre.backtrack_limit', '5000000');

Solution for cause C

You need to determine which plugin or whether the theme contains the error.

Please create a staging page to isolate the problem. We recommend WP Staging (https://de.wordpress.org/plugins/wp-staging/ or https://wp-staging.com/).

After you have created the staging page, log in to the staging page and deactivate all plugins except Borlabs Cookie. Then check whether the problem still occurs. If not, reactivate one plugin after the other and check after each activation of a plugin whether the problem occurs again. This way you can determine whether and which plugin is causing a problem.