Problem sending an email in a SP Workflow

Hello,

I work wiht MSSP2010 Foundation.

I have a workflow implemented in a develop local machine. The application sends several emails to different users involved in the workflow. My application and the workflow run ok.

Then I create a package and I update the application in a pre-production server. In this pre-production server the WF work ok, but 1 of the 4 possibles emails never is sent to the final user. The other 3 possible emails run well.

I think that, the problem with the email that never run, must be related with the sharepoint configuration on the pre-production server.

What configuration could I check in order to detecting the problem?

Thank you in advanced for any idea.

Regards,

María