Ajax Register incompatibility with contact enhance

Hi, I'm writing to you because your Ajax register extensión has an incompatibility with an extension that I use called contact enhance. When I activate the "user plugin" it shows me the following error helix 0

Joomla \ CMS \ Form \ Form :: SetField `Xml` Is Not An Instance Of SimpleXMLElement

I also got in touch with them but they told me that you are the ones who have to give me a solution.

Thanks in advance for the help

Hello, does anyone give support to ajax register anymore? I have requested through contact form, e-mail, and also here!! no answering at all!!

Warning: require_once(/home2/XXXX/public_html/XXXXX/libraries/joomla/document/html/renderer/head.php): failed to open stream: No such file or directory in /home2/globalc1/public_html/XXXXX/templates/global_helix3/error.php on line 42

Fatal error: require_once(): Failed opening required '/home2/XXXX/public_html/XXXXXX/libraries/joomla/document/html/renderer/head.php' (include_path='/home2/XXXXX/public_html/XXXXX/plugins/system/shlib/shl_packages//ZendFramework-1.11.7-minimal/library:.:/opt/alt/php71/usr/share/pear') in /home2/XXXXX/public_html/XXXX/templates/global_helix3/error.php on line 42

Hello,

Not sure it's the problem with AJAX Register but I will have a look.
Will be in touch by email.