Publication Failed in Test Mode

I have a new publication which i built today, It is the exact duplicate of a publication i built a few weeks ago. Only difference is the report which is being sent (the report itself is built on the same universe as the previous publication as well.)

However , when i test or even schedule the publication it fails and the error message reads:

"2012-10-01 16:18:32,939 ERROR [PublishingService:HandlerPool-120] BusinessObjects_PublicationAdminErrorLog_Instance_162062 - [Publication ID # 162062] - Distribution to destination CrystalEnterprise.Smtp (To: abc) failed. Recipient: abc, Document Scope: Provider Universe : 162073 (Excel) : (OR ). write error. [[CrystalEnterprise.Smtp] ([1]/[1])]: [Error sending mail message to SMTP server. Return code: [].] (FBE60013) [1 recipients processed.] "

I did tested the previous publication the same way in test mode and it completed successfully.
I checked all the destination paths of our severs in CMC and they are all configured properly, any idea what else i should be looking at?

Thanks in advance,