call_user_func_array() expects parameter 1 to be a valid callback

• krikey

• October 1, 2021 at 5:53 am

I’m getting a warning currently with my install as follows:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘my_acf_op_init’ not found or invalid function name in /var/www/vhosts/site.domain/httpdocs/wp-includes/class-wp-hook.php on line 292

Can anyone shed any light on why this might be happening?

• John Huebner

• October 1, 2021 at 8:54 am

Somewhere in your code you have a line that looks something like this
add_filter('some-hook-name', 'my_acf_op_init');
or
add_action('some-hook-name', 'my_acf_op_init');
the first part is the hook, the error does not indicate what hook it is on. The second part is the function to be called, that function does not exist.