HubSpot form notification delivery issue

Smart CRM & Sales Hub
1

Hello HubSpot Support,

I am experiencing an ongoing delivery problem with HubSpot form submission notification emails to info@timbertops.nz. The notifications stopped arriving on 5 August 2026.

Notifications from the same form are being delivered successfully to a second HubSpot user with a Gmail address, so the form submission and notification trigger appear to be working. The issue appears to affect delivery specifically to the info@timbertops.nz mailbox.

Our mail host’s Technical Team has completed an investigation and confirmed:

  • The MX records for the domain are correctly configured.

  • The mailbox is otherwise receiving email normally.

  • Exim logs show that HubSpot attempted direct SMTP delivery to the backend hosting server rather than the published MX mail cluster.

  • The backend server correctly rejected the connection because it is not intended to receive mail directly for hosted domains.

  • The relevant log entry states: “Rejected direct delivery… Deliver to mx01/mailcluster.com.au”

HubSpot’s current bounce lookup also shows no bounce data for info@timbertops.nz.

Please investigate the outbound delivery records for this recipient from 5 August 2026 onward and confirm:

  1. Which hostname and IP address HubSpot selected for delivery.

  2. Whether the delivery used the domain’s MX records or another cached or resolved route.

  3. Why the connection was made to the backend server instead of the published MX host.

  4. Whether any DNS-resolution or routing cache needs to be refreshed or corrected.

Please escalate this to the appropriate email-delivery or infrastructure team.

2

Hi @MartinHunter

Just a quick note: the HubSpot Community is a peer-to-peer forum where HubSpot users share knowledge and help each other out, rather than a direct line to HubSpot’s support or infrastructure teams.

One thing worth trying in the meantime: since your mail host’s logs show HubSpot’s delivery being rejected at the server level, it may be worth asking them to allowlist HubSpot’s sending IPs so connections aren’t blocked regardless of the route taken. HubSpot’s IP ranges for allowlisting can be found here.

Let us know how that goes :slight_smile:

Cassie, Community Manager

4

Since the same form notifications are still reaching the Gmail recipient, I agree this does not look like a form or workflow problem.

The interesting part is the hosting team’s evidence showing HubSpot attempting delivery to a backend server instead of the current MX target. If the MX records are correct and other senders are reaching the mailbox normally, this points more toward a stale DNS resolution or cached route on the sending side.

Also ask the mail host to confirm whether the backend server IP has ever appeared in the domain’s MX records, and when the current MX records were changed. That might help explain why HubSpot would still be trying that route.

At this point, HubSpot support probably needs to check the SMTP delivery logs for the recipient and see exactly what hostname and IP their mail infrastructure resolved. The fact that their bounce lookup shows nothing also makes the issue harder to diagnose from the HubSpot side. The host’s Exim log showing the rejected connection should give support something concrete to trace.

5

Hi Guys, thank you so much for your help looking into this.

My host has reviewed the Exim mail logs for info@timbertops.nz and searched specifically for traffic involving HubSpot. They replied

"At this stage, we have not found any rejected or blocked connection from HubSpot that would correspond to the missing form notification emails. As a result, there is no specific Exim rejection log that we can provide to HubSpot for the missing messages.

In fact, the logs show that HubSpot’s mail servers are able to connect to and deliver messages to your mailbox successfully. For example, we can see several recent messages from HubSpot being accepted by our mail server."

The ones that are getting through are the Hubspot emails from Sales and Community, the form notification emails are still not arriving at this host - the alternate gmail address is still receiving these.

The last successful delivery was on the 5/7 and not 5/8 as previously stated.

I’m not sure what to do next, I don’t really have anything to give Hubspot support.

Cheers

6

Regarding the MX record question

The server’s current mail configuration does not indicate that the backend/server IP is being used as the domain’s MX destination. The MX record points to the following mail cluster records:

=host -t mx timbertops.nz

timbertops.nz mail is handled by 20 mx02.mailcluster.com.au.

timbertops.nz mail is handled by 10 mx01.mailcluster.com.au.

However, determining whether that IP address was ever previously listed in the MX records would require historical DNS information. Our current mail logs and DNS configuration cannot reliably establish when a previous MX record was changed or what it contained before the current configuration