Error with plugin AutoSEO

hello, here is an error I have when I use the Autoseo plugin. do you have any idea to fix this? I have this error when using the “timer” skeleton. thank you

Whoops \ Exception \ ErrorException (E_WARNING)
mb_ereg_replace(): mbregex search failure in php_mbereg_replace_exec(): retry-limit-in-match over


            if (is_callable ( $replacement)) {
                $text = preg_replace_callback ($regex, $replacement, $text);
            } else {
                $text = preg_replace ($regex, $replacement, $text);
        $text=str_replace(".\n", '.', $text);
        $text=str_replace("\n", '.', $text);
        $text=str_replace('"', '', $text);
        return htmlspecialchars($text, ENT_QUOTES, 'UTF-8');
    private function cleanText ($content, $config) {
        $length = $config['description.length'];       
        if ($length <=1 ) $length=20; 
        $content = $this->cleanMarkdown($content);
        // truncate the content to the number of words set in config
        **$contentSmall = mb_ereg_replace('((\w+\W*){'.$length.'}(\w+))(.*)', '${1}', $content); // beware if content is less than length words, it will be nulled**    
        if ($contentSmall == '' ) $contentSmall = $content;
        return $contentSmall;

@marc63400, The best place to ask these kind of questions is at the source: The repo of the developer…

Unfortunately, the repo states that all development on AutoSEO is on hold and the issue will therefor probably not be solved:

Unhappily, due to lack of Time, all development on this plugin are on hold.If someone wants to restart the development, He will be welcome…

You might want to look for another seo plugin.