Successful message sent but not receiving in email

I have had this contact form for awhile now and all of a sudden i am not receiving the messages that are submitted. It says the message had been sent successfully but are not coming through to my inbox. I have also done testers since i thought it could be my email itself – but thats not the issue.

I am guessing this has been down for awhile without me even noticing. Is there any solution? And am i able to get access to messages that have been submitted in the past that I have not received?

https://www.cockatours.com/contact/