New users unable to register

When my users go to the site and attempt to register they get an error message upon clicking the “Complete Sign Up”blank page and this is what they get:
Website https://www.theroute360.com
The website cannot display the page
HTTP 500
Most likely causes:
?The website is under maintenance.
?The website has a programming error.

What you can try:
Refresh the page.

Go back to the previous page.

More information

This error (HTTP 500 Internal Server Error) means that the website you are visiting had a server problem which prevented the webpage from displaying.

For more information about HTTP errors, see Help.

I am using WordPress 3.51 and Buddpress 1.7.
Everything else seems to be working fine.