Error code in header

We noticed the same issue for few users who have had malicious code in WordPress code what caused this problem with header.php template.

Problem like this may appears usually when header.php template of website is modified by some plugin or with custom php code inserted into header.php template.
Make sure please that problem isn’t caused by third party plugin.

The solution: If plugins deactivation and theme reinstall will not help, try please reinstall wordpress right from your WordPress Dashboard > Updates page – there is button for that.