Sending email using SMTP

NETMF & Gadgeteer
1

Hi, I’m testing the SMTP class found on codeshare to send an email(https://www.ghielectronics.com/community/codeshare/entry/327), but I have some problems:

I connect to internet and in the Network_Up function:

   void wifiRS21_NetworkUp(GTM.Module.NetworkModule sender, GTM.Module.NetworkModule.NetworkState state)
            {
                Debug.Print("Network up");

                SmtpClient mySmtp;

                mySmtp = new SmtpClient("smtp.gmx.com", 25);

                mySmtp.Send("myemail@gmx.com", "myemail@gmx.com", "wow", "woow", true, "myemail@gmx.com", "my pass");
                Debug.Print("Email sent");
            }

I’m using gmx email because it does not require SSL
Debugging I’ve got the first response=250(auth ok), then is 530 and then 500, so it does not work properly
Finally I’ve got an exception:

#### Exception System.ArgumentNullException - 0x00000000 (1) ####
    #### Message: 
    #### System.Int16::Parse [IP: 0006] ####
    #### Provaemail.SmtpClient::Send [IP: 0094] ####
    #### Provaemail.Program::wifiRS21_NetworkUp [IP: 0028] ####
    #### Gadgeteer.Modules.Module+NetworkModule::OnNetworkEvent [IP: 0049] ####
    #### System.Reflection.MethodBase::Invoke [IP: 0000] ####
    #### Gadgeteer.Program::DoOperation [IP: 001a] ####
    #### Microsoft.SPOT.Dispatcher::PushFrameImpl [IP: 0054] ####
    #### Microsoft.SPOT.Dispatcher::PushFrame [IP: 001a] ####
    #### Microsoft.SPOT.Dispatcher::Run [IP: 0006] ####
    #### Gadgeteer.Program::Run [IP: 001d] ####
A first chance exception of type 'System.ArgumentNullException' occurred in mscorlib.dll
Error invoking method "Gadgeteer.Modules.Module+NetworkModule" (check arguments to Program.BeginInvoke are correct)

Do you have any advise?
Thank you

2

Actually nearly all e-mail server require ssl or tls secured transmission and authentication . The driver from Codeshare doesn’t provide that. In another Codeshare project I used Sparkpost to send e-mails but some days ago they posted that it is not longer free of charge for low quantities.

Oops: Just saw that the provider you selected doesn’t require ssl. :slight_smile:

3

Response 530 could be an authentication failure message. You might need to debug more to understand it.

4

Google search for smtp error message 530 shows that it means access denied.
A possible approach to find the reason could be porting the NETMF SMTP Class to a PC and watch the network traffic with e.g. wireshark and compare the network traffic generated by the NETMF Class with the network traffic of a regular PC e-mail client which successfully works with the gmx server.
I would be interested to find an e-mail provider which doesn’t require ssl too. To evtl. set up the application on my side, which mainboard are you using?

5

I’m using the Fez Spider II
The username and password are surely correct, maybe tomorrow I will test another email provider or use wireshark as you said (which ip address do I have to monitor? I connect the Spider II using the wifi but monitoring that ip gives nothing, while if I set the PC ip a lot of stuff appear)

6

Hi,
Seems that gmx.com doesn’t support anymore non-SSL connections for years…
(gmx smtp server problem or https://www.dataloggerinc.com/resource-article/non-ssl-smtp-servers-use-datataker-devices/)

HTH

7

Wireshark won’t see your device because it will be through an effective switch in the router. You could try Wireshark in promiscuous mode but I doubt it will work.

The only way to see the data is with a network HUB and connecting the Spider via hardwired Ethernet instead.

8

Thank you, as said in the last post of the first link you sent, I created a smtp2go account with gmx username and password, and now it gives me 503 error.
I tested the configuration adding an account to gmail, using gmx email and password and smtp2go server and it worked, I can send email. So the system works, but the code gives me error, so maybe there’s an error in the smtp_class? But this user said it worked using another webemail https://www.ghielectronics.com/community/forum/topic?id=5426&page=3#msg154260

9

I ment run The Code on The PC, not The Spider

10

Hi,
You can send/type all SMTP commands with telnet which gives you a chance to determine which command generates the error.

11

Below is a link to some code I tested with links is some good references. I hope it helps;

12

I tested with telnet, and everything is ok, I received the email

EDIT. I made it, there was an error on line 67-> HELO instead of EHLO, now it works, thank you to everybody
I updated the codeshare class with only this modification

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