Can I send email with mailgun sandbox domain under my local OS?

Question

I registered myself at mailgun with domain I use for my laravel apps

Also I see that with my domain there is sandbox domain, which looks like :

sandboxdXXXXXXXXXXXXXXXXXXXX.mailgun.org

and under SMTP block I see text: Grab your SMTP credentials:

SMTP hostname: smtp.mailgun.org
Port: 587 (recommended)
Username: postmaster@sandboxdXXXXXXXXXXXXXXXXXXXX.mailgun.org
Default password: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX-XXXXXXXXXXXXXXXX

Working on my local OS, apache 2 under ubuntu 18 I try to send email in my local having in .env :

MAIL_DRIVER=mailgun
MAIL_HOST=smtp.mailgun.org
MAIL_PORT=587
MAIL_USERNAME=postmaster@sandboxdXXXXXXXXXXXXXXXXXXXX.mailgun.org
MAIL_PASSWORD=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX-XXXXXXXXXXXXXXXX
MAIL_ENCRYPTION=tls
MAIL_FROM_ADDRESS='from_email@site.com'
MAIL_FROM_NAME='FROM NAME'
MAILGUN_SECRET='XXXXXX-XXXXXXX'
MAILGUN_DOMAIN='sandboxdXXXXXXXXXXXXXXXXXXXX.mailgun.org'

As result I sent email without errors, But I did not receive emails for 2 my users which are in Authorized Recipients of mailgun.

What for this sandbox domain, can I use it for local OS and can I send emails under my local OS ?

UPDATED : In my local .env I set mailtrap.io params and it works ok.

In Account Security->API security->API keys of my mailgun account I have parameters L

Private API key 
Public validation key 
HTTP webhook signing key

Setting app on remote dev server

MAIL_MAILER=smtp
MAIL_DRIVER=mailgun
MAIL_HOST=smtp.mailgun.org
MAIL_PORT=587
MAIL_USERNAME=XXX
MAIL_PASSWORD=XXX
MAIL_ENCRYPTION=tls
MAIL_FROM_ADDRESS='from_email@site.com'
MAIL_FROM_NAME='FROM NAME'

If MAIL_USERNAME and MAIL_PASSWORD must be filled with values from Account Security->API security->API keys also if MAIL_FROM_ADDRESS must one of Authorized Recipients I created in the settings before ?

UPDATED BLOCK 2: I try to fill parameters from live domain, but failed. I search paramters here : https://prnt.sc/18ouojv ?

Thanks in advance!

Answer 1

As Sandbox domains are restricted to authorized recipients only.So make sure to verify recipients emails in

https://app.mailgun.com/app/sending/domains

If recipients has not received email to inbox then check in spam folder.

Ref: https://help.mailgun.com/hc/en-us/articles/360011702394-Why-Do-My-Emails-Go-to-Spam-

If still not working then change mailer to smtp

MAIL_MAILER=smtp

Then run

php artisan config:clear

Env

MAIL_MAILER=smtp
MAIL_HOST=smtp.mailgun.org
MAIL_PORT=587
MAIL_USERNAME=postmaster@sandbox**************.mailgun.org
MAIL_PASSWORD=************************
MAIL_ENCRYPTION=tls
MAIL_FROM_ADDRESS=youraccountemailaddress
MAIL_FROM_NAME="${APP_NAME}"

Answer 2

I would not use the sandbox domain, as it has problems, does not work like a real domain and there is no reason to not start with the real domain for free .
Short description to start with MailGun with your own domain:

• Create an account at mailgun including a credit card
  -> If you don't add a credit card, you will not be able to use MG
  -> This don't means, that you have to pay unless you don't reach the limit
  of 5'000 emails / month
• add your (existing) domain in MG (only possible, if you have added a CC)
  under "Sending" - button "Add new Domain" (Button only visible if a CC is added)
• follow exactly the steps that are showed at the right top corner
  in the MG portal. Title "Getting started"
  You have to reach 100% before you will be able to send your first emails
  Note:
  This also includes "illogical" steps - eg send an email to mailgun@YourDomain
  although, a mailbox "mailgun" does not exist
  You further have to send an email to yourself
  These steps seems to be needed for initial verification at MG
• add exactly the DNS entries from the MG portal (spf and mta) to your domain
  To do this you need access to the portal of your domain provider
• in MG - under DNS Records - press button "Verify DNS settings"
  the DNS settings have to be verified (a green check is showed), before you can send emails
• If anything is OK, you will receive an eMail from MG:
  Good news! The DNS settings you added for YourDomain have been verifyed.
• If you have received this email, you should be able to send emails over MG

Further notes to development (I work with Visual Studio 2017, Windows Forms and vb.net):
I had to set TLS 1.2 to be able to connect:
vb.net code:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12

I further have added the NuGet package: RestSharp (as the code examples in MG are based on RestSharp).
Code example for vb.net (after adding the NuGet to RestSharp):

    Imports System.Net
    Imports System.Net.Mail
    Imports RestSharp
    Imports RestSharp.Authenticators 
    ...
    Dim client As RestClient = New RestClient()
    client.BaseUrl = New Uri("https://api.eu.mailgun.net/v3/")
    Dim cAPIKey As String = "YourKey from MG"
    client.Authenticator = New HttpBasicAuthenticator("api", cAPIKey)
    Dim request As RestRequest = New RestRequest()
    request.AddParameter("domain", "YourDomain", ParameterType.UrlSegment)
    request.Resource = "{domain}/messages"
    request.AddParameter("from", "Your Description <Mailbox@YourDomain>")
   ' add mail address(es): 
     request.AddParameter("to", "mail-address1")
   ' further, if needed  (Note: I send a single email to each recipient): 
     request.AddParameter("to", "mail-address2")
   ' add bcc mail address (if needed): 
     request.AddParameter("bcc", "bcc-mail-address")
   ' fill the mail:   
     request.AddParameter("subject", cMailBetreff)
     request.AddParameter("html", cHTMLMailBody)
     request.Method = Method.POST
     Dim status As IRestResponse
     status = client.Execute(request)
   ' state handling:     
     If status.StatusCode.ToString = "OK" Then
      ' O.K handling
     Else
       ' Error handling
     End If

Notes to the code above:
I send a complex html, that I have stored in a file that is loaded in the variable cHTMLMailBody.
After the load, some variables in the file are change to customer values stored on a SQL server (cMailBetreff also contains a customer specific generated text).
As I'm not from thee USA, I have to use the url: https://api.eu.mailgun.net/v3/" .
If you are from the USA, you have to use another url (see MG portal).

Notes to the error handling in MG (Log in MG):
I have done some tests with the code above (that works). As I also want to know (and store), if the sent email has reached the recipient, I have done some tests and sent emails to a not existing domain and an existing domain, but not existing mailbox.
To the not existing domain, an error was logged in MG (what is correct). To the not existing mailbox, the state OK was logged in MG (what is wrong ). The reason to the wrong state (OK) to the not existing mailbox was, that MG don't receive non delivery mails, if there is no MX record to the domain that targets the MG server. As we (manually) also send out emails to the domain from our own mail server, I don't wanted to change the mx record to our domain in general to the MG server.
Therefore I have added a sub domain to our domain (in MG and also at our DNS provider) and then added a MX record to the new sub domain that points to the MG server.
Then, I have changed the domain parameter to SubDomain.Domain:

  request.AddParameter("domain", "SD.Domain", ParameterType.UrlSegment)

The problem then was, that a not nice "on behalf of" was generated automatically in the header. I was able to solve the issue by adding a further parameter:

    request.AddParameter("h:sender", "Your Description <Mailbox@YourDomain>")

(same value as in from parameter, whereby the h: is needed in addition) After doing that, MG also receives non delivery emails and add also an error to not existing mailboxes.

So.. if you need to get/store the states to the sent emails and don't want to change your mx record generally to MG, you should add a sub domain (if not, you should not need a sub-domain).

For me, everything now seems to work as it should:

• we can sed out html mails over MG
• we can capture the states to the sent emails over the MG API
• we still can send (manually) emails over our own mail server
  And important:
• if a recipient answers to an email, the answer is delivered to our mailbox on our server

Hope this helps somebody...