Encountering a fatal error like Uncaught Error: Call to Undefined Function get_header can be alarming, as it disrupts your website's functionality.
This error typically occurs due to issues in your theme or WordPress setup, such as missing files or incorrect function calls.
This article will explore the common causes of this error and provide step-by-step solutions to resolve it. Follow our guide to get your website back up and running smoothly.
Reinstall the Divi theme with access to the WordPress Dashboard
Download a fresh copy of Divi from your Elegant Theme's account
Go to WordPress Dashboard → Appearance → Themes → Add new
Choose the
zipfile downloaded at step 1Install Divi
Note: Since Divi is already installed on the server, WordPress will display the following message: This theme is already installed.
Click on the Replace active with uploaded button.
Ensure that the error is not a 3rd party plugin conflict or Child Theme conflict
Go to WordPress Dashboard → Divi → Support Center
Enable the Safe Mode
Check again and see if the error still appears
Note: While the Safe Mode is active, all 3rd party plugins, child themes, and any other custom code will be deactivated. This only applies to the currently logged-in user. The website's visitors will not be affected by the Safe Mode being active.
Reinstall the Divi theme without access to the WordPress Dashboard
Using the hosting File Manager app or an FTP connection, navigate to the wp-content/themes folder
Rename the Divi folder to something else(such as Divi-old) - this should give you back access to WordPress Dashboard
Log in to your WordPress Dashboard
Go to Appearance → Themes and delete the current Divi installation
Download a fresh copy of Divi from your Elegant Theme's account
Go to WordPress Dashboard → Appearance → Themes → Add new
Choose the zip file downloaded at step 5
Install Divi
Note: if you are also using a Child theme, after Divi was reinstalled, activate the Divi theme instead of the child theme. This will help you rule out any possible issues that might be created by the current Child theme
Rename the plugins folder
Using the hosting File Manager app or an FTP connection, navigate to the wp-content folder
Rename the plugins folder to something else(such as plugins-old)
Check if the issue is solved
If the issue is solved after renaming the plugins folder:
Log in to your WordPress Dashboard - all your plugins will be disabled from the previous step.
Rename the plugins folder from your temporary name back to plugins
Go to Plugins and start activating one plugin at a time
After each activation, check if the issue is solved