Nylas Email Integration Incident Report
As of July 24, 2025 HTR became aware of an bug with our 3rd party email integration provider Nylas caused by an outage with Google's Gmail APIs.
- Status 🔴 In Progress
- Feature Impact Email integration
- Users Impacted Users who have connected a Gmail account via the feature
- Scope of Issue In select cases where the Gmail API returned errors, its possible that emails were sent 2 or 3 times to a user when they were retried. Our estimate is that 20-30% of users were impacted
Who is impacted?
Only select users who currently have implemented the email integration feature and connected a Gmail account (Outlook and other providers do not have this same issue Learn more). If you want to confirm impact you can go to the sent mail tab of your Gmail account that you integrated and search for the subject line of the campaign and then see if any users were sent duplicative emails.
Context of what happened
On July 20, 2025 a client reported that they had sent a review campaign using the email integration and that some users were reporting that they had received duplicates of certain emails.
Since emails sent via this integration get sent triggered via the Nylas API and then sent through your own email (Gmail, Outlook, etc), HTR does not have visibility into the emails that are sent. As such, we quickly acted to implement the following:
- Refactor the feature to queue up each email as its own job (instead of queueing up a campaign with multiple emails batched) to ensure that if a single email event fails, when the job retries it then it only retries that email (instead of the entire campaign)
- Implement webhooks from the Nylas API to receive and log a response to each email event that we sent to gain visibility into which emails sent, which returned an error and which were retried.
After implementing these changes and gaining visibility into the errors we found that they continued to persist so we became fairly certain that these were caused by the Nylas API and went to reach out to their customer support to then find in their user forums a discussion thread about this being a known recent issue as well as an active bug report on their status page detailing the root cause of the issue which is in reality a bug with Google's Gmail APIs.
What are we doing about it?
For users who have the Nylas email integration feature enabled but don't currently have an active campaign running...we disconnected all user accounts who had integrated their email and disabled the Nylas email integration feature in the HTR dashboard to ensure that new campaigns won't be sent until this issue is resolved.
For users who have an active campaign running...we are reaching out to you individually with an update and next steps so we can keep active campaigns running until completion and then disable the feature once they are complete.
As noted above, the root cause of the issue is an error in Google's Gmail APIs which Nylas is waiting to hear back from Google's customer support about (you can subscribe to updates here). We are now monitoring the status of this option issue between Google and Nylas awaiting a resolution.
Our dev team is investigating options available to implement safeguards to ensure that even if Google's Gmail API or Nylas' API have errors, that we have controls in place to prevent them from impacting campaigns sent using this integration. We are also investigating alternative email integration APIs on the market as a backup in case we deem Nylas' tool not to be stable enough to re-activate.
If you have any users who have reached out frustrated about this issue please note that:
- The biggest impact a single user would experience is just receiving a duplicate of a review request email
- If you would like our team to reach out to impacted users to explain the issue that Google and Nylas and by effect HTR, we are happy to so please reach out via the live chat on site