Skip to content

Technical requirements for connecting your inbox to HubSpot using IMAP

Last updated: January 29, 2024

Available with any of the following subscriptions, except where noted:

All products and plans

To connect your inbox to HubSpot, your email server must support IMAP (Internet Message Access Protocol) and SMTP (Simple Mail Transfer Protocol). Below you'll find the requirements for connecting your inbox using IMAP.

This article has technical resources and definitions meant for your IT team or your email administrator. If your email server is not currently set up for IMAP, please work with your IT administrator to make sure your inbox is configured correctly.

Please note: the conversations inbox does not support an IMAP connection. If you are trying to connect an email account to the conversations inbox, you need to connect an inbox that is hosted with either Gmail or Office 365.

Server requirements

When you connect your inbox to HubSpot and send emails, HubSpot connects with your email server over TLS (Transport Layer Security). To access the inbox and submit mail, IMAP and SMTP are used, respectively. Both ports running these protocols must be open to traffic, or you may add the IPs making these connections to your allowlist.

HubSpot will make up to five concurrent connections when you have an inbox connected with IMAP.

  • While connected, there are two permanent concurrent connections so HubSpot can sync emails from the inbox and from the sent folder.
  • There is also a third permanent connection made if your inbox has additional folders.
  • Two temporary concurrent connections also occur when you send an email through your connected inbox in HubSpot.

The port that HubSpot connects to must support encryption. HubSpot supports TLSv1.0, TLSv1.1, TLSv1.2, SSLv3 or STARTTLS upgrade to TLSv1.0, TLSv1.1, TLSv1.2, SSLv3 on all ports; TLSv2 is not supported.

HubSpot does not support an inbox connection if your server uses Courier-IMAP as the IMAP software. This is because HubSpot is not able to log email replies to the CRM when replies are sent to an inbox using Courier-IMAP software.

The Common Name (CN) for the SSL certificate installed on the server must include the fully qualified domain name (FQDN) of the server that HubSpot is connecting to. For example, if your IMAP server is, the CN on the SSL certificate must include


Your email configuration can affect your ability to connect your inbox via IMAP:

  • IMAP must be enabled in order to sync mail.
  • HubSpot does not support a connection with ActiveSync, but if you use ActiveSync in your email client, connect your account using the HubSpot-Exchange connection.

Security certificate

In the case that your SSL certificates are not signed by a Certificate Authority, there is an option to allow a non-secure certificate when initiating the connection. You'll need the appropriate username and password to access your server as well as the IMAP and SMTP server names. Follow these instructions to obtain this information or work with your IT team to determine the correct login credentials to use.

Add IP addresses to your allowlist

Your IT team might only allow certain IP addresses to connect with your inbox. If this is the case, your IT team will need to add the IP addresses HubSpot uses to connect your inbox to your allowlist.

Because authentication methods, security settings, and available protocols can differ from one email server to another, it may be necessary to work with your IT team to confirm that your email server meets the above requirements. If you experience any difficulty during the IMAP connection process, work with your IT team or administrator when you open a ticket with HubSpot Support, as your IT department can provide specific information needed to troubleshoot that HubSpot does not have access to.

Was this article helpful?
This form is used for documentation feedback only. Learn how to get help with HubSpot.