You also want to check your anti-virus software and firewalls and be sure DatabaseMail is permitted.
what were the results of your initial investigation? have you checked the logs in sql and in windows?
I have written an article about this, maybe it could help http://coffeeandsql.com/2013/09/17/debugging-database-mail-issues-in-your-sql-server-with-t-sql/
hi both u of u thanks .Issue was my server was not listed in exchange server .it is what network guy who work tell told me , but any ways thanks got many queries thanks to Carlaabanes