Hi, I'm using XOOPS 2.0.x. I have setup my mail server on Administration->Preferences ->Mail Setup so if someone registered they can activate there account on there email, but I haven't succeed on it. My SMTP is smtp.xxyyzz.com.

It gaves me the following error when somebody registered:

You are now registered. However, we were unable to send the activation mail to your email account due to an internal error that had occurred on our server. We are sorry for the inconvenience, please send the webmaster an email notifying him/her of the situation.

Please help me in fixing this problem

Thanks,
JP