I am here to provide a config file sample to show how to configure a smtp server in reporting service 2005.

config file: reportingserviceinstallationdirreportserverrsreportserver.config

<Extension Name="Report Server Email" Type="Microsoft.ReportingServices.EmailDeliveryProvider.EmailProvider,ReportingServicesEmailDeliveryProvider">
<MaxRetries>3</MaxRetries>
<SecondsBeforeRetry>900</SecondsBeforeRetry>
<Configuration>
<RSEmailDPConfiguration>
<SMTPServer>[servername.domainname]</SMTPServer>
<SMTPServerPort></SMTPServerPort>
<SMTPAccountName>[a valid account]</SMTPAccountName>
<SMTPConnectionTimeout></SMTPConnectionTimeout>
<SMTPServerPickupDirectory></SMTPServerPickupDirectory>
<SMTPUseSSL></SMTPUseSSL>
<SendUsing>[2, this is important]</SendUsing>
<SMTPAuthenticate>[0, this is important]</SMTPAuthenticate>
<From>[a valid email]</From>
<EmbeddedRenderFormats>
<RenderingExtension>MHTML</RenderingExtension>
</EmbeddedRenderFormats>
<PrivilegedUserRenderFormats></PrivilegedUserRenderFormats>
<ExcludedRenderFormats>
<RenderingExtension>HTMLOWC</RenderingExtension>
<RenderingExtension>NULL</RenderingExtension>
<RenderingExtension>RGDI</RenderingExtension>
</ExcludedRenderFormats>
<SendEmailToUserAlias>True</SendEmailToUserAlias>
<DefaultHostName></DefaultHostName>
<PermittedHosts></PermittedHosts>
</RSEmailDPConfiguration>
</Configuration>
</Extension>