Deprecated: mysql_real_escape_string()

My client is getting errors with this plugin on their site.

I recreated the issue

https://demo.veganwebdev.com/

with TwentyFourteen and no other plugins activated but this one, and get the following

Deprecated: mysql_real_escape_string(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in /home/veganweb/public_html/demo/wp-content/plugins/marquee-style-rss-news-ticker/marquee-style-rss-news-ticker-3-0-0.php on line 318

Warning: mysql_real_escape_string(): Access denied for user ‘veganweb’@’localhost’ (using password: NO) in /home/veganweb/public_html/demo/wp-content/plugins/marquee-style-rss-news-ticker/marquee-style-rss-news-ticker-3-0-0.php on line 318

Could this be a conflict with the recent WP updates?

https://www.ads-software.com/plugins/marquee-style-rss-news-ticker/