Email (SMTP) Configuration

concorbit uses SMTP to send all outbound email: campaigns, portal sign-in links, invoice emails, payment receipts, and system notifications. The SMTP settings page lets you configure one or more email providers, set up a custom sending domain, and monitor delivery health.

URL: /settings/smtp
Required permission: settings.tenant

Accessing SMTP Settings

1. Go to Settings from the sidebar.

2. Click the SMTP card (described as "Outbound email transport, campaigns, portal links, invoice emails").

How Email Routing Works

concorbit's MailerService routes outbound email across your configured SMTP providers using weighted load balancing and automatic failover:

1. Weight-based distribution: Each provider has a routing weight. Higher weight = more sends. A provider with weight 200 receives roughly twice as many emails as one with weight 100.

2. Daily limits: Each provider has a configurable daily send limit. Once reached, the provider is excluded from routing for the rest of the day.

3. Rate limiting: Per-minute rate limits prevent you from exceeding your provider's throughput cap.

4. Health monitoring: concorbit tracks whether each provider is healthy or failing. Failing providers are automatically skipped until manually marked healthy.

5. Failover: If the selected provider fails, the system automatically retries through the next available provider.

If you have not configured any SMTP providers, concorbit falls back to a shared platform mailer with a daily quota. This is suitable for initial setup but not for production use, configure your own provider to remove the daily cap.

Platform Email Service

The SMTP page displays a Platform email service card showing your current month's email usage:

• Free sends: Every workspace gets a monthly quota of free sends (enough for password resets and basic transactional email).

• Charged sends: Emails beyond the free quota are charged at a per-1,000 rate (displayed on the card).

• Pending charges: The accumulated overage charges for the current month, billed at month-end.

A progress bar shows how much of your free quota has been used. Configure your own SMTP provider to bypass the platform email service entirely and send unlimited emails with no platform charges.

Custom Sending Domain

The custom sending domain card at the top of the SMTP page lets you send emails from your own domain (e.g., noreply@yourcompany.com) instead of from @concorbit.com.

Setting Up a Custom Domain

1. Click Set up (or Manage if already configured) on the custom sending domain card.

2. You are taken to the Email Domain page at /settings/email/domain.

3. Enter your domain (e.g., yourcompany.com).

4. concorbit registers the domain with the email service and generates DNS records you need to add.

Adding DNS Records

After registering your domain, you must add the following DNS records with your domain registrar or DNS provider:

DKIM (DomainKeys Identified Mail)

Add a TXT record for email authentication. The exact hostname and value are displayed on the verification page. DKIM cryptographically signs your emails so receiving servers can verify they genuinely came from your domain.

Example:

Type:  TXT
Host:  concorbit._domainkey.yourcompany.com
Value: k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GN...

Return-Path CNAME

Add a CNAME record for bounce handling. This ensures bounced emails are routed back to concorbit for processing.

Example:

Type:  CNAME
Host:  pm-bounces.yourcompany.com
Value: pm.mtasv.net

SPF (Sender Policy Framework)

If you do not already have an SPF record, create one. If you do, add concorbit's sending servers to your existing record:

v=spf1 include:spf.mtasv.net ~all

DMARC

While not strictly required, a DMARC record is recommended for maximum deliverability:

Type:  TXT
Host:  _dmarc.yourcompany.com
Value: v=DMARC1; p=none; rua=mailto:dmarc@yourcompany.com

Verification

After adding DNS records, return to the Email Domain page and click Verify. concorbit checks for the DKIM and Return-Path records. The domain progresses through these states:

DNS propagation can take up to 48 hours. If verification fails, wait and try again.

Updating the From Identity

Once your domain is fully verified, you can configure:

• From name: The display name on outbound emails (e.g., "Your Company").

• From address: The sender email address (e.g., noreply@yourcompany.com).

Removing a Custom Domain

Click Remove on the Email Domain page to delete the custom domain. Emails will revert to the platform sender address (@concorbit.com).

Adding an SMTP Provider

1. Click Add provider on the SMTP page.

2. Fill in the provider form:

1. Click Save.

Managing Multiple Providers

concorbit supports multiple SMTP providers simultaneously. This is useful for:

• Redundancy: If one provider goes down, email continues through the others.

• Load distribution: Spread sends across providers to stay within individual provider limits.

• Provider migration: Add the new provider, shift weight gradually, then remove the old one.

Editing a Provider

1. Click Edit on the provider row.

2. Update the fields. When editing, the Host, Username, and Password fields are optional, leave them blank to keep the existing values.

3. Click Save.

Removing a Provider

1. Click Remove on the provider row.

2. Confirm in the dialog.

If this was your only provider, emails will fall back to the platform mailer.

Health Monitoring

Each provider displays a health status badge:

Daily Quota Bar

Each provider shows a progress bar indicating how many of its daily sends have been used. The bar changes colour:

• Green: under 75% of the daily limit.

• Amber: between 75% and 95%.

• Red: over 95%.

Last Error

If a provider has encountered errors, the most recent error message is displayed below the provider name. This helps diagnose configuration issues.

Marking a Provider Healthy

When a failing provider's issue has been resolved (e.g., you updated credentials or the provider's outage ended):

1. Click Mark healthy on the provider row.

2. The provider returns to the routing pool immediately.

Testing

Connection Test

Click Test on any provider row to verify the SMTP connection. concorbit attempts to connect to the SMTP server and authenticate. A success or failure flash message appears.

Send Test Email

1. Click Send test in the top-right corner.

2. Enter a recipient email address.

3. Click Send.

This dispatches a real email through the full multi-provider routing pipeline, including failover logic and email logging. Use it to verify your entire configuration end-to-end.

Troubleshooting Delivery Issues

Emails Not Sending

1. Check provider health: Are any providers marked as "Failing"? Check the last error message.

2. Check daily limits: Has the provider exhausted its daily quota?

3. Check rate limits: Is the per-minute rate limit too low for your send volume?

4. Check credentials: Edit the provider and re-enter the password.

5. Run a connection test: Click "Test" to verify the SMTP connection.

Emails Landing in Spam

1. Set up a custom sending domain with proper DKIM, SPF, and DMARC records.

2. Verify DKIM is working: Check the email headers of a test email for a DKIM-Signature header.

3. Check SPF alignment: Ensure your SPF record includes your SMTP provider.

4. Add a DMARC record: Even a p=none policy improves deliverability.

5. Use a reputable From address: Avoid free email domains (gmail.com, outlook.com) as your From address.

Platform Fallback Quota Exhausted

If you see the "Email sending paused" banner on the Settings hub:

1. Navigate to SMTP settings.

2. Add your own SMTP provider (any provider, even a free-tier Mailgun or SendGrid account).

3. Once configured, the daily cap is removed and queued emails will start sending.

Common SMTP Provider Settings

Related Documentation

• Brand & White-Label Settings, email header branding and footer customisation.

• Workspace Settings, inbound email configuration.

• Subscription & Billing, email usage charges on your monthly bill.