scaleway · Loic-kd · May 6, 2026
@@ -58,6 +58,10 @@ Refer to the [Understanding managed dedicated IPs](/transactional-email/referenc
 
 ## Access and security
 
+### Why can't I connect to the SMTP server?
+
+Refer to the [dedicated troubleshooting page](/transactional-email/troubleshooting/smtp-connection/) for more information.
+
 ### Can I authorize sending emails from specific IP addresses?
 
 Yes. You can authorize sending emails from a specific IP address by [configuring conditions in IAM policies](/iam/reference-content/understanding-policy-conditions/).

@@ -52,6 +52,7 @@ productIcon: TransactionalEmailProductIcon
 ## Transactional Email troubleshooting pages
 
 <LinksList>
+  - [I cannot connect to an SMTP server](/transactional-email/troubleshooting/smtp-connection)
   - [Getting delisted from Spamhaus](/transactional-email/troubleshooting/delist-domain)
   - [Emails take a long time to send](/transactional-email/troubleshooting/long-sending-time)
 </LinksList>
@@ -0,0 +1,44 @@
+---
+title: I cannot connect to an SMTP server
+description: This page helps you understand and fix the connection to an SMTP server
+tags: transactional email smtp smtp-server connection troubleshooting
+dates:
+  validation: 2026-05-05
+  posted: 2026-05-05
+---
+
+## Problem
+
+I cannot connect to an SMTP server.
+
+## Cause
+
+- The SMTP ports are disabled.
+- Using wrong credentials (e.g., email address as username instead of the Project ID).
+
+## Solution 
+
+### Enable SMTP ports on a Scaleway Instance
+
+By default, the SMTP ports (587, 465, and 2465) are disabled on all Scaleway Instances. To enable them:
+1. Click **CPU & GPU Instances** in the **Compute** section of the side menu. The [Instances page](https://console.scaleway.com/instance/servers) displays.
+2. Select the Availability Zone (AZ) from the drop-down menu (e.g., `PAR1`) to view resources in the selected AZ.
+3. Click the **Security groups** tab. The **Security groups** dashboard displays.
+4. Click the security group you want to edit.
+5. Tick the **Enable SMTP** box to allow outgoing emails.
+
+### Enable SMTP ports on other environments
+
+|     Environment      |                                                                                     How to enable SMTP                                                                                      |
+| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| Serverless Container | No action required. SMTP ports are blocked on Serverless Containers except for Transactional Email.                                                                    |
+| Serverless Function  | Read our [tutorial to send emails with Transactional Email and Serverless Functions using the Serverless Framework](/tutorials/send-emails-tem-serverless-framework/) for more information. |
+| Kubernetes           | Enable SMTP via Public Gateway and Security group of nodes.                                                                                                                                      |
+
+### Verify your SMTP credentials
+
+Make sure you use the correct credentials:
+- Hostname : `smtp.tem.scaleway.com`
+- Port : `587` (STARTTLS), `465` (SSL), or `2465` (TLS)
+- Username : your Project ID
+- Password : your API Token with [Transactional Email permissions](/iam/reference-content/permission-sets/#transactional-emails)