Topic: Error - Mailbox unavailable. The server response was 5.7.1 unable to relay for
This happens when your SMTP is not configured to your localhost
1. Open IIS
2. Right-click on "Default SMTP Virtual Server" and select "Properties"
3. Click on the "Access" tab
4. Click on the "Relay..." button
5. Click the "Add..." button
6. Enter "" for your localhost account
7. Click "OK", "OK", "OK"
8. Try your app
You'll need to make sure the following tags in BLUE are in your Web.Config
<configuration xmlns="">
            <remove name="LocalSqlServer"/>
            <add name="LocalSqlServer" connectionString=
                        "Data Source=MySource;&#xA; Initial Catalog=MyAp;&#xA;
                         Integrated Security=True" providerName="System.Data.SqlClient"/>
            <authentication mode="Forms"/>
            <compilation debug="true"/></system.web>
                  <smtp from="">
                        <network host="localhost" password="" userName=""/>