PHP Warning: json_encode(): Invalid UTF-8 /my_path/class/class.utils.inc.php

[uploadraagjatt]

Hello sir, today i bought PHP sitemap generator script from your official website. There is an issue when i execute runcrawl.php file this show my sitemap is generated but file is missing sitemap.xml which is genrated even my path is absolutely right, Solve this issue asap

showing the error -
PHP Warning:  json_encode(): Invalid UTF-8 sequence in argument in /var/www/vhosts/dj-punjab.info/raagjatt.com/gsitemap/pages/class.utils.inc.php on line 254

[XML-Sitemaps Support]

Hello,

please let me know your generator URL/login in private message to check this.