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Send emails with Mailcoach

Add PostShiba as a Mailcoach SMTP mailer.

What you'll build

A Mailcoach mailer that delivers your campaigns and automation emails through PostShiba over SMTP. Mailcoach keeps your lists, campaigns, and unsubscribe links. PostShiba delivers the mail and suppresses addresses that hard bounce or report spam.

This page covers Mailcoach Cloud, which accepts your own SMTP provider. Mailcoach does not track opens, clicks, bounces, or complaints for mail sent over SMTP.

Before you start

  • A Marketing cluster. Newsletters belong on a bulk cluster, not a transactional one, and the type is locked after create. See Clusters.
  • An SMTP username and password. Open your cluster in the dashboard, go to its SMTP credentials, and choose Create SMTP credential. Copy the password right away, because it is shown once. You can also use the SMTP credentials API.
  • A verified sending domain. See Add and verify a domain. Each list's From email must be on it.
  • A cluster that is ready to send (sending_ready is true).
  • A Mailcoach Cloud account.

Install

Nothing to install. Mailcoach has SMTP support built in.

Pick a plan for your largest list

PostShiba caps each cluster per hour and per rolling 24 hours. The 24-hour cap must cover your largest list plus anything else the cluster sends that day.

Plan Emails per hour Emails per 24 hours Mailcoach throttling (mails every 1 second)
Nano 100 600 Test sends only
Micro 4,000 24,000 1
Small 40,000 240,000 11
Medium 100,000 600,000 27
Large 200,000 1,200,000 55

When a cap is full, SMTP answers 451 4.7.0 hourly send limit reached or 451 4.7.0 daily send limit reached and does not keep the message. Select Resize on the cluster page before a campaign that would go over. See What happens at your cap.

Send your first email

  1. In Mailcoach, go to Configuration → Mailers. Enter a Name, choose SMTP as the Email service, and select Create new mailer.
  2. On the SMTP settings step, enter these values and select Verify. The username starts with smtp_. Choose TLS for Encryption. With port 587 it upgrades the connection with STARTTLS.
mailcoach-smtp.txt
1Host: smtp.postshiba.com 2Port: 587 3Username: smtp_9 4Password: YOUR_PASSWORD 5Encryption: TLS
  1. On the throttling step, set Send to the value for your plan from the table above and every to 1 second. Select Save.
  2. In the mailers list, select Make default, or pick the mailer as the Campaign mailer in your list's settings.
  3. In your list's settings, set From email to an address on your verified domain, such as hello@mail.example.com.
  4. Open a campaign's content and select Save and send test to send it to your own address. The message shows under Events in the PostShiba dashboard.

Every SMTP setting is on Send emails with SMTP.

Bounces, complaints, and unsubscribes

Mailcoach learns about bounces and complaints from its email provider's feedback. Over SMTP it gets none, and PostShiba bounce messages come back to PostShiba, because the return-path points at PostShiba.

Event What happens
Hard bounce PostShiba suppresses the address. Later sends to it are refused with 550 suppressed.
Spam report PostShiba suppresses the address the same way.
Soft bounce PostShiba retries delivery. Nothing is suppressed.
Unsubscribe Mailcoach adds its own List-Unsubscribe and List-Unsubscribe-Post headers, so PostShiba leaves them alone. Mailcoach marks the subscriber as unsubscribed.

Suppressed addresses still look active in Mailcoach. PostShiba refuses them, so they never reach a mailbox, but they stay in your subscriber counts. Copy suppressions into Mailcoach now and then.

Copy suppressions into Mailcoach

Mailcoach adds suppressions one at a time under Configuration → Suppressions, or through its API. For more than a few addresses, use the API.

  1. Export every suppressed address to postshiba-suppressions.csv. Follow How do I export my suppression list?. It takes a read-only Support key and one script. The file has one address per line.
  2. Create an API token in your Mailcoach account.
  3. Run this script with your Mailcoach address and token. It stays under the Mailcoach API limit of 5 requests per second.
mailcoach-suppressions.sh
1MAILCOACH_URL=https://YOUR_MAILCOACH_DOMAIN 2MAILCOACH_TOKEN=YOUR_MAILCOACH_TOKEN 3 4while read -r email; do 5 curl -s -X POST "$MAILCOACH_URL/api/suppressions" \ 6 -H "Authorization: Bearer $MAILCOACH_TOKEN" \ 7 -H "Accept: application/json" \ 8 -H "Content-Type: application/json" \ 9 -d "{\"email\": \"$email\"}" 10 sleep 0.25 11done < postshiba-suppressions.csv

Run it again after each large campaign. Mailcoach then skips those addresses in every list.

Troubleshooting

What you see What to do
Verify fails Check Host, Port, Username, and Password. Use port 587 with TLS. Port 465 is not offered. PostShiba accepts AUTH PLAIN only.
550 unverified domain or 550 from header not aligned with verified domain Set the list's From email to an address on your verified domain.
550 kyc_required Your team is pending production approval. Until then, send only to team members, live inbox addresses, and inbox forward-to addresses. See Does PostShiba require production approval?.
550 suppressed The subscriber hard bounced or reported spam. Copy suppressions into Mailcoach as shown above.
451 4.7.0 hourly send limit reached or 451 4.7.0 daily send limit reached The cluster is at its cap and did not keep the message. Lower the mailer's throttling, or resize the cluster before the next campaign.
451 4.4.5 too many sessions, slow down Mailcoach opened too many SMTP connections on one username in 10 seconds. Lower the mailer's throttling.
421 4.3.2 ... idle too long The connection sat idle for 30 seconds and PostShiba closed it. This is not throttling. See 421 4.3.2 idle too long.
No opens or clicks in Mailcoach Mailcoach does not track opens and clicks for mail sent over SMTP.

Next steps