Dear Sirs, good day to you all.
I have made a project 10 years ago using Motorola G24 modules. They where larger, with many connections but for this purpose very similar in general. But, at that time, the security policies of the providers were lighter. Today I am having trouble to send my first reporting email.

Some days ago the opportunity of a similar data reporting project arrived and I bought a SIM800L.
I could quickly setup, send and receive SMS and configure NTP. I downloaded all the available literature from SIMCOM’s site. I am not a GSM/GPRS expert myself. I am just an analog/ digital hardware and software designer. I am sorry for my inexperience with SIM800.

I applied the example listed in the SIMCOM documentation on sending email: “SIM800 Series Email Application Note V1.02.pdf” and “SIM800 Series SSL Application Note V1.05.pdf”

I have regular working email accounts with the 3 providers. Please accept the following sequence listing of the AT commands used, where there are not syntax or other errors reported by the SIM800L module. Each command is accepted and confirmed, except for the last one, when sending the email message. I am receiving this kind of errors:

+SMTPSEND: 65 // SMTP server response error
+SMTPSEND: 67 // Authentication failed. SMTP user name or password may be not right

It seems that there is some problem with authentication or the protocols envolved in such process. I eliminated the “OK” replies from the module to make more readable. Please be so kind to indicate where my error is? Thank you in advance.

AT+SAPBR=3,1,”APN”,”CMNET” // Configure bearer profile 1
AT+SAPBR=1,1 // To open a GPRS context.
AT+EMAILCID=1 //Set parameters of Email
AT+EMAILTO=30 OK //Set timeout
AT+EMAILSSL=1 // use SSL for specified port
AT+SMTPSRV=””,587 //Set SMTP server address and port
AT+SMTPAUTH=1,"","mypass" // user & pass AT+SMTPFROM="",“Bob” // FROM:
AT+SMTPRCPT=0,0,“``”,“Robert” // TO:
AT+SMTPBODY=13 // here goes a 13 char msg
DOWNLOAD // SIM800 prompts for sending text
This is a test // email text …
AT+SMTPSEND // send it
… wait
+SMTPSEND: 67 // email was not send

Hi, @microlatina
I have the same module and I’m trying the exact same thing but I got only +SMTPSEND: 61 error code. So, did you find anything new so far?

Hello ! Thank you for your post.

I could finally have a solution to the problem.

Th SIM800L works perfectly well in 2G (lets asume that this is an almost obsolete module) and I could finally send, receive email and SMS with no problems.

So where is the problem? The answer is: the major mail servers don’t want you to send email over SMTP if you don’t use qualified or certified originating tools. This is a security problem.

Although the web sites of all of these major servers such as Gmail, Yahoo, Outlook (Hotmail) and the like offer the possibility of using their mailer servers to send over SMTP and also receive using POP3 or IMAP protocols. The original historical ports SMTP 25 and POP3 110 have changed because these original protocols were rather innocent in front of the actual June 2023 hackers or spammers. So they have added new layers of security protocols such as SSL and TLS. Port 465 is used for implicit TLS, STARTTLS on port 587, adding encryption security to the email traffic. Some qualified email servers accept the traditional ports 25, 2525 and 110 but also support the newer 465, 587 and 995 for POP3.

I some cases such as Yahoo and Gmail, you will be asked to obtain a special password for access email traffic through their mailer server different of the usual login password used to access your account as usual. But if you take your time to read the small letters, you will be guided through a numbers of steps, generally including that you have a qualified registered domain that must be also provided. Also, instructions are given for some proprietary APIs that are offered and that you can download usually for WordPress or similar platforms.

In my case I decided to subscribe to a simpler qualified mail server service that can be found across the internet. These servers offer excellent and fast service for almost unlimited numbers of messages at different affordable rates. Also, all hosting services offer access to your mail account via SMTP and POP3 provided that you have a registered qualified domain you can point to. Using this solution, the mighty SIM800L stopped throwing these +SMTPSEND: 67 or 61, etc and finally gave me +SMTPSEND: 1 meaning that the message was accepted by the mailer server.

I repeat, the email examples of the SIMCOM data sheet work perfectly well an these sticky errors mean that the servers are refusing your transaction because you do not qualify for their security standards.

An extra advice: transactions using GPRS modules must be short, must begin → use → end, in a short time. Once you are provided an IP address, you should use it quickly and drop it. Telco providers don’t like too much that you keep a dynamic IP for ever and very frequently. If you need almost permanent connections for reporting short messages there are special protocols such as MQTT that are Telco friendly and do the job.

Google “Yahoo (Gmail, Outlook) settings for SMTP” the official versions.

Now happy with my SIM800L, I hope that this information could be of use.
Greetings from Buenos Aires, Argentina !

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THANK YOU for your reply @microlatina,
I am new to this module, and can you modify my AT commands for me in this thread just for clarification for me? Also which mail should I prefer? (protonmail or another would you like to prefer)

Thank you for your attention…

Hello BehicMV, I suggest you use exactly the command sequence that I have posted before because this is the one that finally lead me to success when I used the correct email server. You can check sites such as SMTP2GO. There are many of these. Open a free account there and then start testing. Please consider SPAM traffic. The providers are very cautious and sensitive about SPAM. So try to use the resource normally. GSM/GPRS modules are intended for the generation of short reports at reasonable frequencies. Good luck !

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