Registration problem
 

We have recently installed vB3.81. I installed Cyb Advanced Registration plugin too in it.(Thought it is now removed)
I added all staff via ACP just add user.
Now that we are almost near to go live and we wanted to do some testing on registration, we are facing this strange error. I hope here is someone to help.
The problem is that once a user clicks on Register, simply it goes to the registration form and filling up the form. Then click on Submit. After that HTTP 500 error appears and says the site is either under maintenance or there is some problem in programming.
All help is appreciated and thank you in advance.

Anyone knows anything about it?

We found this problem. This thread can be locked.
It was one of our custom modifications desinged for us. We will work it out.
Thank you.