Common PHP errors and how to fix them

First, find the full error message. It’s in the error_log file in your website’s folder, or in wp-content/debug.log for WordPress. See Finding PHP error logs. The message names the file and line number where PHP found the problem.

Parse error: syntax error, unexpected …

PHP Parse error: syntax error, unexpected identifier "echo" in /home/cpuser/public_html/functions.php on line 25

Older PHP versions say unexpected T_STRING, unexpected T_VARIABLE or unexpected end of file. They all mean the code isn’t written correctly, so PHP can’t read it. Usually it’s a small typo on that line or the line just before it:

• a missing semicolon ; at the end of the previous line
• a missing or extra quote ' or ", bracket ) or brace }
• a curly quote (’ or “) pasted from a word processor or website, instead of a straight quote

unexpected end of file usually means a { was never closed.

To fix it: open the file in File Manager’s code editor, go to the line number, and check that line and the one above it. If you just edited the file, undo your change. If the file belongs to a plugin or theme you didn’t edit, reinstall or update it.

Fatal error: Cannot redeclare …

PHP Fatal error: Cannot redeclare my_function() (previously declared in /home/cpuser/public_html/wp-content/themes/mytheme/functions.php:10)

The same function is defined twice. Common causes:

• the same code was pasted twice into functions.php or another file
• two plugins, or a plugin and your theme, include the same code
• a file is loaded with include or require more than once

To fix it: remove the duplicate function, or turn off one of the two plugins. In your own code, use require_once instead of require, or wrap the function in if ( ! function_exists( 'my_function' ) ) { … }.

Fatal error: Call to undefined function …

PHP Fatal error: Uncaught Error: Call to undefined function mb_strlen()

Either the function’s PHP extension is turned off, or the function was removed from your PHP version.

Function starts with	Turn on this extension
mb_	mbstring
imagecreate, imagejpeg, getimagesize	gd
curl_	curl
mysqli_	mysqli (or nd_mysqli)
zip_, ZipArchive	zip
intl, Normalizer, NumberFormatter	intl
simplexml_, dom	simplexml, dom
sodium_	sodium

Turn extensions on in cPanel under Select PHP Version → Extensions. See Changing your PHP version and settings.

If the function is mysql_connect(), each(), create_function() or ereg(), it was removed in PHP 7 or 8. Update the script, or as a short-term fix switch to an older PHP version.

Allowed memory size exhausted

A script used more memory than memory_limit allows. See PHP memory limit vs your plan’s RAM.

Maximum execution time of 60 seconds exceeded

A script ran longer than max_execution_time. Raise it in Select PHP Version → Options (for example to 300), or run long jobs such as imports and backups as a cron job.

Warning: Cannot modify header information – headers already sent

PHP Warning: Cannot modify header information - headers already sent by (output started at /home/cpuser/public_html/wp-config.php:1)

Something was sent to the browser before the page header, often a blank line or space before <?php, or after a closing ?>. Open the file named after output started at, and remove any spaces or empty lines before <?php at the top and after ?> at the end. Saving the file as “UTF-8 without BOM” also helps.

Uncaught Error: Class “…” not found

A PHP class can’t be found. Usually a file is missing, Composer packages weren’t installed (vendor folder missing), or a PHP extension is off. Re-upload the app’s files, run composer install, or check the extension list above.

Deprecated: … and Warning: …

These aren’t errors that stop your site. Deprecated means the code will stop working in a future PHP version; Warning means something unexpected happened but the script carried on. Update the plugin, theme or script that’s named. They’re logged, not shown to visitors, unless display_errors is On.

Errors after changing PHP version

If errors started right after you changed your PHP version, switch back to the previous version in Select PHP Version, then update your software before trying again. See Resolving common PHP upgrade issues.

Still stuck? Open a support ticket with the full error message and the page’s address.