Sometimes it happened when this kind of issue came you did everything according to basic rules for database mail setting in SQL Server and when you try to send the mail through SQL server you got error
"Exception Type: System.NullReferenceException
Message: Object reference not set to an instance of an object.
TargetSite: Microsoft.SqlServer.Management.SqlIMail.Server.Objects.Account GetAccount(Int32)”
When you tried to resolve it you search a lot of google you did not get a proper result.
I faced this problem with SQL Server 2005 edition with SQL Server Service Pack1.
Here I am sharing how simple to resolve this. Simplest step is to Update SQL server service Pack 2 & SQL server service pack 3.
You can download SQL server service pack 2 with link http://www.microsoft.com/en-us/download/details.aspx?id=9969
and SQL server Service pack 3 with link http://www.microsoft.com/en-us/download/details.aspx?id=14752
Once you install it and after restart your SQL server mail function started Isn’t it simple.
I hope this resolve the problem of my friends who searched a lot on Google but could not get a proper solution.
Thanks & Best Regards,