Hello,
Please install the Email Log plugin from wp.org to make a log of the emails that your site is creating.
There are several possible reasons for the issue you describe.
1. Host blocking – The host may be blocking the email from being sent. In this case you can make alterations to the subject and body, and if that doesn’t work, contact the host to request support.
2. GD not creating the email – unless changes have been made to the plugin files, the function should work, but in rare cases if the email is not listed in the log, we can take a deeper look to identify the issue.
In both cases the log helps everyone understand where the problem is, so, install the log and then try to send an enquiry and let us know what you find iout.
https://wpgeodirectory.com/docs/useful-plugins/#email