How to fix Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback)

The error message indicates a TypeError that occurred in the call_user_func_array() function. This function is used to call a callback function with a given set of parameters. To help you further, I’ll need more information about the context in which this error is happening.

However, in general, this error can occur if you’re passing an invalid callback to call_user_func_array(). The callback should be a valid callable, such as a function name, a closure, or an array containing an object and a method name.

Here are a few common scenarios that can lead to this error:

1. Incorrect callback format: Ensure that the callback you’re passing to call_user_func_array() is in the correct format. For example, if you’re using a function name, make sure you’re passing it as a string.
2. Missing function or method: If you’re using a function name or a method as a callback, ensure that the corresponding function or method exists and is accessible from the current scope.
3. Incorrect object method: If you’re using an object method as a callback, make sure you’re passing an array with the object instance and the method name. For example: [$object, 'methodName'].
4. Mismatched number of arguments: Verify that the number of arguments you’re passing to call_user_func_array() matches the expected number of parameters for the callback function.

By examining the code and understanding the context in which the error occurs, you can identify the specific issue causing this error and resolve it accordingly.

If the error “Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback)” in a WordPress site, it typically means that there is an issue with a callback function or hook in your code. Here are a few common causes and possible solutions:

1. Incorrect usage of hooks: In WordPress, hooks are used to trigger actions or filters at specific points during the execution of a page. If you’re using a hook incorrectly or specifying an invalid callback function, it can lead to this error. Review the code where the hook is defined or used and ensure that the callback function exists and is defined correctly.
2. Plugin or theme compatibility issue: If the error started occurring after installing or updating a plugin or theme, it’s possible that there is a compatibility issue. Try disabling the recently installed/updated plugins or themes one by one to identify the problematic one. Once you’ve identified the culprit, you can contact the plugin/theme developer for support or look for any available updates.
3. Plugin conflict: Conflicts between different plugins can also cause this error. Disable all plugins except the essential ones (e.g., security plugins) and see if the error persists. If it resolves the issue, gradually re-enable the other plugins one by one until you find the one causing the conflict.
4. Theme-related issue: If the error is related to a theme function or template file, try switching to a default WordPress theme (e.g., Twenty Twenty-One) temporarily and see if the error persists. If the error disappears, the issue is likely with your theme. Contact the theme developer for assistance or consider updating to the latest version.
5. PHP version compatibility: Check the PHP version your WordPress site is using. Some plugins or themes may require a specific PHP version, and using an incompatible version can result in errors. Ensure that your PHP version meets the requirements of your plugins and themes.

If none of these solutions resolve the issue, it may be necessary to provide more specific details about the code or the steps leading to the error to further assist you in troubleshooting the problem.