what's the server role for database mail on sql server 2008?

Question

I have create a account and assign server role as public. the assign user mapping on database mydb as dbo, and for msdb also as dbo.

with User mapping setting on msdb, I checked following role:

DatabaseMailUserRole
db_owner
public

then my app login with this account and try to send out email with database mail profile. and I got error as:

System.Data.SqlClient.SqlException: The EXECUTE permission was denied on the object 'sp_send_dbmail', database 'msdb', schema 'dbo'.

If I assign server role sysadmin to this account. then it's working fine.

but I don't want to assign sysadmin to this account. how to resolve this issue?

Weird thing is I also try it on testing server. that account even not in DatabaseMailUserRole on msdb, it's working fine.

The only difference on 2 sql sever box is SMTP authentication setting:
On testing box, is set as "Basic Authentication"
On production box, is set as "Windows Authentication using Database Engine service credentials"

Hi Bridge. Thanks. run EXEC msdb.dbo.sysmail_help_principalprofile_sp and got following on production:

principal_id    principal_name  profile_id  profile_name    is_default
11      guest       1       sqlservice  0
12      mydomainaccount 1       sqlservice  0

On staging, no result.

Answer 1

To send Database mail, users must be a user in the msdb database and a member of the DatabaseMailUserRole database role in the msdb database. To add msdb users or groups to this role use SQL Server Management Studio or execute the following statement for the user or role that needs to send Database Mail.

EXEC msdb.dbo.sp_addrolemember @rolename = 'DatabaseMailUserRole'
    ,@membername = '<user or role name>';
GO

Source: http://technet.microsoft.com/en-us/library/ms188719%28v=sql.100%29.aspx