Invalid Certificate

[CrimesWorld]

I am currently having some problems sending the Newsletter for my site.

Last week I sent it with no problems and this week, whenever I try to send it I get an error that says


You have received an invalid certificate. Contact server admin (blah blah blah)

Your certificate contains the same serial numberas another certificate issued by the certificate authority. Please get a new certificate containing a unique serial number

Then it says it failed to send the SMTP message through my SMTP mail.crimesworld.com even though it worked last week.

Anyone can help?

Thanks in advance
- CrimesWorld