why mail not reaching in workflows

Hi guys,

I have been trying to find out why mails sent in wordflows not reaching the user? I searched this site and found out that we can configure using SOST tcode but i could not find any clue there. When i execute workflow then i see that it is complete then also i cant see the mail (sap internal mail)gone to the user. I replaced the user with myself but then also nothing happened. Please help me what should i do?

Thanks

Adit