Introduction
When using the Google / Gmail or Microsoft 365 / Outlook integrations to send email through Gravity SMTP, it’s essential to understand how these general account-based services may fail compared to dedicated email delivery services that are built for this purpose, like Postmark or Mailgun.
When connecting your Google or Microsoft account, you provide access to an entire suite of capabilities linked to that account—not just SMTP functionality. As such, these organizations enforce stricter (and constantly evolving) security policies and procedures, which can impact email sending. The most common we have noted so far is that an action or event taken outside of Gravity SMTP can result in the Google/Microsoft account demanding re-authentication, and until that is noticed and completed, your integration will stop sending emails.
This article covers some of the events we have noticed so far that can cause such disruption.
Events That Can Force Re-Authentication
A connected Google or Microsoft account may be required to re-authenticate whenever the provider’s (evolving) security policies demand. Gravity SMTP customer reports have demonstrated the following events as often requiring re-authentication:
- Changing the password for the connected account.
- Enable Two-Factor Authentication (2FA) after the initial connection.
Initiating these actions (which take place outside of Gravity SMTP) can result in a service disconnection, which will kill your Gravity SMTP integration until corrected.
We at Gravity SMTP believe a dedicated email provider service is the right choice for your website when you have a choice, but we offer some advice that may help below.
Consider Alternative Email Delivery Services
We recommend email integrations explicitly designed for transactional emails. Services like Postmark, Mailgun, or SendGrid offer a more stable and seamless experience for sending emails. Additionally, such services provide much more targeted user guides and documentation, and more accessible support teams with email-delivery troubleshooting experience that may be easier to reach and quicker to resolve issues than you might experience with Google or Microsoft.
Transactional mailers are also optimized for deliverability, ensuring your emails reliably reach inboxes, and they usually provide detailed logging and analytics, allowing you to track delivery status, open rates, and bounce reports—features that are not available when sending through Google or Microsoft.
| Benefits | Google/ Gmail – Microsoft / Outlook 365 | Dedicated Transactional Email Services |
|---|---|---|
| Require Re-authentication | Yes | No |
| Optimized for Transactional Email | No | Yes |
| Better Deliverability | No | Yes |
When is it OK to use Google Or Microsoft?
As mentioned above, we always default to recommending the use of a dedicated transactional email service wherever possible, but Google/Microsoft SMTP might still be appropriate for:
- Low-volume websites with emails sent mainly for personal or simple purposes.
- Low-importance tasks where occasional losses due to unexpected disconnection aren’t business critical.
- Organizations that may have strict policies requiring the use of their own email servers.
- Testing or setup validation prior to service launch.
Minimizing Google/Microsoft Email Deliverability Issues
If you still choose to use the Google or Microsoft integration, consider these best practices to minimize disruptions:
- Use an App Password (if available) instead of a regular password to reduce re-authentication issues.
- Set up Gravity SMTP email alerts to notify you if authentication fails so you can act quickly.
- Regularly check your integration settings to ensure you’re still connected.
Alternatively, you can find a supported dedicated transactional email service in our list of available Gravity SMTP integrations.