ERROR: Couldn’t register you… please contact the webmaster !

Hi,

I hope someone could help me. My website has been working fine. Many have registered in the past until recent. Someone brought this up to my attention.

My website is no longer allowing people to register. I keep getting the following message regardless of the length of the email address and name (I thought that was the problem).

“ERROR: Couldn’t register you… please contact the webmaster !”

I have tried disabling and enabling plugins to no avail

Please help

EDIT: I am going to try and update to the latest wordpress. Crossing fingers.