Custom SMTP Configuration

Custom SMTP allows your company to send all GTR system and marketing emails directly through your own mail server instead of through GTR’s email infrastructure.

This option is typically used by companies with strict IT/security policies, those who want full control over deliverability, or organizations already using a centralized email service (e.g., Microsoft 365, Google Workspace, etc.).

You can configure SMTP under:

Settings → Sender Configuration → Custom SMTP

Note: Only one sending method can be active at a time.

Until your SMTP settings are successfully validated, emails will continue to be sent from:
donotreply@getthereferral.com

Before You Begin

Firewall Whitelisting

If your mail server is behind a firewall, you must whitelist the following IP address to allow GTR to send email through your server:

50.18.0.11

Without whitelisting, the Test & Save process will fail.

Provider-Specific Requirements

Gmail / Google Workspace

SMTP Host: smtp.gmail.com
Google requires an App Password for SMTP
Create one here:
https://support.google.com/accounts/answer/185833?hl=en
2-Step Verification must be enabled on the Google account.

Outlook / Microsoft 365

SMTP Host: smtp-mail.outlook.com
SMTP Client Authentication must be enabled for the mailbox:
https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/authenticated-client-smtp-submission#enable-smtp-auth-for-specific-mailboxes
If MFA is enabled, you must use an App Password.

What You’ll Need

To complete your SMTP configuration, gather the following:

SMTP Host
SMTP Port (typically 587, 465, or 25)
Username
Password / App Password
Security Type (SSL, TLS, or StartTLS)
From Name
From Address

The Test & Save button will only activate once all fields are valid.

1. Navigate to Custom SMTP Configuration Settings

Log in to your GTR Admin dashboard account
Go to Settings → Sender Configuration
Select the Custom SMTP option

The SMTP configuration form will appear with all required fields.

2. Enter Your SMTP Credentials

Fill in the required fields:

SMTP Settings

SMTP Host
Port
Security Type (SSL, TLS, StartTLS)
Username
Password (or App Password)

Sender Identity

From Name (display name for email recipients)
From Address (must match the mailbox used for SMTP)

3. Test & Save Your SMTP Configuration

Click Test & Save to validate your settings.

If the test succeeds:

The configuration is saved
Custom SMTP becomes the active sending method
All emails will be sent through your server

If the test fails:

You will see an error message explaining the issue.
Common causes include:

Incorrect credentials
App Password not used
SMTP AUTH disabled
Firewall blocking traffic
Wrong security type or port