Connect Amazon SES to NetSendo

Before you start

• A NetSendo account. SMTP mailboxes work on every licence; NetSendo does not check the licence for them.
• SES in a Region with an SMTP endpoint. The host is email-smtp.<region>.amazonaws.com, for example email-smtp.eu-central-1.amazonaws.com (Frankfurt). Not every Region has one; see the AWS endpoints page.
• A verified identity in that Region: your domain (recommended, because SES then signs with DKIM; see SPF, DKIM and DMARC) or the one address you send from. SES console: Configuration → Identities → Create identity.
• SES SMTP credentials for that Region: SES console, SMTP settings → Create SMTP Credentials. They are not your AWS access keys, they work only in that Region, and AWS shows the password once.
• Sandbox or production. New SES accounts are in the sandbox in every Region: mail only to verified addresses, at most 200 messages per 24 hours and 1 per second. Request production access under Account dashboard → View Get set up page → Request production access.

Steps

1. In NetSendo, open Settings → Mailboxes.
2. Click Add Mailbox (on an empty page the button is Add First Mailbox).
3. Under Provider, select SMTP.
4. In Mailbox Name, type a name you will recognise, for example Amazon SES.
5. In From Email, enter an address on your verified SES identity, for example news@example.com.
6. Optionally, enter a Reply To address.
7. In From Name, type the sender name your subscribers will see.
8. In SMTP Host, enter your Region's endpoint, for example email-smtp.eu-central-1.amazonaws.com.
9. In Port, type 587. The field starts empty.
10. In Encryption, select TLS. Select SSL only if you use port 465.
11. In Username and Password, paste the SES SMTP user name and SMTP password.
12. Under Allowed Message Types, keep ticked what this mailbox should send: One-time (Broadcast), Autoresponder (Queue) and System. Keep System if your lists should send signup confirmations through SES.
13. In Daily Sending Limit, enter your SES 24-hour quota (for example 200 in the sandbox), or leave it empty for No limit.
14. Click Save.
15. On the new mailbox card, click the Test Connection icon (the check mark).
16. If the card has no Default badge, click Set as Default (the star icon).

For each email NetSendo uses the message's Sending mailbox (message Settings tab), else the list's Default Outbound Mailbox (SMTP) (Contact Lists → Email Lists, Edit, Settings tab, Sending), else the default mailbox. Your first mailbox becomes the default automatically; a mailbox switched off on its card is skipped.

Check that it works

• Test Connection sends a real email with the subject "Connection Test" to the address of the NetSendo user you are signed in as. You see "Connection successful! Test email sent." and the card shows Active. In the sandbox, that address must also be verified in SES.
• Test a real message: open it, click Test, enter an address and click Send test. It arrives with [TEST] before the subject. Tests skip the queue, so they work even before the scheduler runs.
• With a Daily Sending Limit, the card shows Sent Today against the limit.

If it doesn't work

A failed test sets the card to Connection Error and shows the error in red; click it for Connection Error Details.

"535 Authentication Credentials Invalid"

You entered AWS access keys, or SMTP credentials created in another Region. Create SMTP credentials in the endpoint's Region, click Edit on the card and paste the new password. Leaving Password empty keeps the stored one.

"554 Message rejected: Email address is not verified"

The From Email is not on an identity verified in this Region, or your account is in the sandbox and the recipient is not verified. That includes your own address when you click Test Connection. Verify the identity or the recipient, or request production access.

The test times out or cannot connect

Your server or hosting provider blocks the outbound port, or you send from Amazon EC2 on port 25, which EC2 throttles. Use port 587 with TLS (or 2587), or port 465 with SSL (or 2465), and allow outbound traffic to that port. Don't combine SSL with port 587: SSL makes NetSendo start with an encrypted connection (TLS Wrapper), while SES expects STARTTLS on 587.

"454 Throttling failure: Maximum sending rate exceeded"

You send faster than your SES rate. NetSendo retries throttled and other 4xx replies, up to 3 attempts in total with growing delays, then marks the recipient Failed. In Settings → CRON Settings, set Message limit / minute (default 100) below your SES rate, for example under 60 in the sandbox, and click Save settings. Then click Retry under Failed on the campaign's Statistics page.

Recipients fail after the daily limit

At its Daily Sending Limit the mailbox is skipped and NetSendo looks for another one. If it finds none, the remaining recipients are marked Failed with a Polish error saying no active mailbox allows the type. Raise the limit, or Retry the next day. More: Emails not sending.

Campaigns go out through a different mailbox

Check the order above. A mailbox whose Allowed Message Types exclude the message's type is replaced by another mailbox, the default one first.

Bounces are not recorded

Bounce webhooks (shown when you edit a saved mailbox) has no SES tab. Its Other tab accepts a POST with the JSON fields email, bounce_type (hard or soft) and bounce_reason plus the mailbox's Webhook token, so your own script can forward SES bounce notifications. More: configuration docs.

Do it with an AI assistant

The NetSendo MCP server cannot create a mailbox; add it in the panel first. Then an assistant can use list_mailboxes (IDs, From addresses, allowed types), update_contact_list with default_mailbox_id to make it a list's default, update_campaign with mailbox_id for one campaign, and send_campaign_test with mailbox_id to try it. Setup: MCP docs.

List my NetSendo mailboxes, make the Amazon SES mailbox the default mailbox of the list "Newsletter", and send a test of campaign 42 to me@example.com through it.