There is a simple solution if you’re experiencing the error 550 5.7.708 Service unavailable when sending emails from HubSpot with your Office 365 integration.

This is commonly caused because you may have recently signed up for Office 365, or created a new account.

The error is caused because of an issue with the reputation of the IP address issued by Microsoft for your mail server.

You can still send emails through Outlook, but any email sent through HubSpot Sales will generate this 550 5.7.708 service unavailable error.

As you’ve recently created your Office 365 account, your “tenant” account is new, meaning you’ve got a low reputation to start, as is typically the case with new accounts until they’re “warmed up”.

The solution to this is very simple. You need to raise a support ticket or reach out to Microsoft directly.

By providing them with the details from the email that you’ve received from HubSpot (as shown above), they will be able to run a diagnostic repair action on the IP address, and this will resolve the issue.

We find Microsoft support very helpful, and this process should take around 30 – 60 minutes for the team at Microsoft to resolve.