This error message is due to the fact that parameter 1 (string) passed null to the trim() function has been deprecated in PHP 8. This usually means that a variable was not properly initialized or assigned a value before it was passed to the trim() function.

To fix this, you can check if the variable is null before calling the trim() function and handle it appropriately. Example:

<?php
// Assume that $string is the variable you want to pass to trim().
if (isset($string) && !empty($string)) {
    $trimmed_string = trim($string);
} else {
    // Handling of empty or undefined cases
    $trimmed_string = '';
}
?>

This ensures that the variable is initialized and not null before it is passed to the trim() function.
If you encounter this problem when importing a CSV file, you can check the code in the import logic to make sure that all variables passed to the trim() function have been properly assigned values.