Constant Contact API not accepting emails

I’m getting this message after the Constant Contact Form was working fine a couple of days ago.

Deprecated: Function split() is deprecated in /home/content/76/11396076/html/lovingonme.com/wp-content/plugins/constant-contact-api/functions.php on line 938

All help is accepted. I’m handy when told what to do.

http://www.dogoodgirls.us is the site I’m looking to fix the problem on.

Thanks in advance.

http://ww.wp.xz.cn/plugins/constant-contact-api/