I'll preface this with the fact that I'm sure it isn't the forum module, but I'm fresh out of ideas for how to fix it.

So any notifications from my forum module are not being delivered and if I check the EventViewer I see the following message (this includes moderation emails, etc):

"The server rejected one or more recipient addresses. The server response was: 553 Sorry, that domain isn't in my list of allowed rcpthosts" as the inner exception.

My email is hosted through GoDaddy but the website itself is on a dedicated server elsewhere.  My "regular" emails from the DNN instance are going out (registration emails, etc), so it isn't a matter of being configured incorrectly... but I'm not really sure where the problem lies.

Any ideas?

Hi,

I'm using DNN 4.5.3, latest forum module. I'm enocountering a similar issue:

AssemblyVersion: -1
PortalID: -1
PortalName:
UserID: -1
UserName:
ActiveTabID: -1
ActiveTabName:
RawURL:
AbsoluteURL:
AbsoluteURLReferrer:
UserAgent:
DefaultDataProvider:
ExceptionGUID:
InnerException: The server rejected one or more recipient addresses. The server response was: 503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.
FileName:
FileLineNumber: -1
FileColumnNumber: -1
Method:
StackTrace:
Message: System.Web.HttpException: The server rejected one or more recipient addresses. The server response was: 503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server. ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Runtime.InteropServices.COMException (0x8004020F): The server rejected one or more recipient addresses. The server response was: 503 This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server. --- End of inner exception stack trace --- at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters) at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams) at System.Web.Mail.SmtpMail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) --- End of inner exception stack trace --- at System.Web.Mail.SmtpMail.LateBoundAccessHelper.CallMethod(Object obj, String methodName, Object[] args) at System.Web.Mail.SmtpMail.CdoSysHelper.Send(MailMessage message) at System.Web.Mail.SmtpMail.Send(MailMessage message) at DotNetNuke.Modules.Forum.Utils.SendForumMail(Int32 PostID, String URL, ForumEmailType EmailType, String Notes)
Source:
Server Name: WEB09

But I have checked my smtp settings and I receive notifications for the registrations emails and using the admin > newsletter function. I have verified this on both an internal email and a gmail account. Is there a setting in the forums module that I am missing?

Thanks