Hi Francisco,
What DNN version are using? There are known email issues related to DNN 5.6.1 and DNN 6.0.1. If you're on these, I will first recommend that you upgrade your DNN version to at least DNN 6.0.2.
If you're unable to do that, you can follow Chad's comments posted on 1/26/2011 on this forum thread:
http://www.datasprings.com/dnn-modu...-1-problem Please let us know if the problem persists after doing this. Thanks!
Candace