Connect an inbox via SMTP
How to connect any email provider to CarcMail using SMTP credentials — useful for non-Gmail providers or custom domains.
Use SMTP if your inbox is hosted outside of Google — for example, Outlook, Zoho, custom domain email via cPanel, or any other provider.
Overview
SMTP (Simple Mail Transfer Protocol) is a standard way for email software to send mail. CarcMail supports SMTP connections, which means you can connect almost any email account — even a fully custom-domain inbox hosted by your own provider.
To connect via SMTP, you’ll need a few technical details from your email provider: the SMTP hostname, the port number, your email address, and a password (usually an app-specific password rather than your regular login password).
CarcMail encrypts and stores your SMTP credentials securely. They are used only to send and check replies on your behalf.
Gmail users should use the OAuth method instead. Gmail’s security settings make SMTP more complex to set up, and OAuth is the recommended path for Google accounts.
Before you start
- Your email provider's SMTP hostname (e.g. smtp.zoho.com, smtp.office365.com)
- The correct SMTP port — usually 587 (TLS) or 465 (SSL)
- An app password or SMTP-specific credentials from your email provider
- Your full email address (e.g. you@yourcompany.com)
- Two-factor authentication enabled if your provider requires it for app passwords
Where to find your SMTP settings
Most providers publish their SMTP settings in their help documentation. Common ones:
| Provider | SMTP Host | Port |
|---|---|---|
| Outlook / Microsoft 365 | smtp.office365.com | 587 |
| Zoho Mail | smtp.zoho.com | 587 |
| Yahoo Mail | smtp.mail.yahoo.com | 465 |
| Custom cPanel host | mail.yourdomain.com | 587 |
Check your provider’s help centre if your host isn’t listed above.
Step-by-step
Generate an app password from your provider
Most modern email providers require you to create an “app password” — a separate password specifically for third-party apps — rather than using your regular account password.
In Outlook: Go to Microsoft account → Security → Advanced security options → App passwords. In Zoho: Go to My Account → Security → App-specific passwords. In Yahoo: Go to Account security → Generate app password.
Copy the password once it appears — most providers only show it once.
Open inbox settings in CarcMail
From the CarcMail sidebar, go to Settings → Inboxes and click Add inbox. On the connection type screen, select SMTP.
Enter your SMTP credentials
Fill in the connection form:
- Display name: The sender name that recipients will see (e.g. “Alex from CarcMail”)
- Email address: Your full email address
- SMTP host: The hostname from your provider
- SMTP port: 587 (TLS) for most providers; 465 (SSL) if your provider requires it
- Password: The app password you generated in step 1
Leave “TLS/STARTTLS” enabled unless your provider specifically requires it off.
Test and save
Click Test connection. CarcMail will attempt to authenticate with your SMTP server and send a test message. If the test passes, click Save inbox. If it fails, check the error message — the most common causes are an incorrect host, wrong port, or an expired app password.
How to confirm it worked
- The inbox appears in Settings → Inboxes with a green “Connected” badge
- The test email arrives successfully at the test address
- You can select the inbox when creating a new campaign
Common issues
| Issue | What to check |
|---|---|
| ”Authentication failed” | Your app password may be wrong or expired. Generate a new one from your provider. |
| ”Connection timed out” | Your SMTP host or port may be wrong. Double-check with your provider’s documentation. |
| ”TLS negotiation failed” | Try switching from port 587 to 465, or vice versa. Also check whether your provider requires SSL vs STARTTLS. |
| Connected but emails bounce | Your provider may require a verified sending domain. Check your provider’s sending limits or domain authentication requirements. |
Frequently asked questions
You need your SMTP host, port (usually 587 or 465), your email address, and an app password or SMTP credentials from your provider.
SMTP requires storing credentials, while OAuth does not. Both are encrypted. We recommend OAuth (Gmail) where available.
Put it into practice
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