Error with my own App

I recently purchased this app and had it all installed fine. After about a month i had an error with it and i dont know what needs doing to fix it. Anyone help?

Basically, when it wants to authenticate it is stuck in a constant loop and eventually ends in an error after several minutes.

Here is the url
fbookrewards.com/rewards

Check out the error yourself, makes it easier as my explanation is probably bad haha

Thanks in advance