How to connect your own mailboxes for cold email

Send cold email from your own Google Workspace or other mailboxes. Otto reads only the replies and bounce reports to its cold emails, and you can disconnect a mailbox at any time.

Updated 2026-10-30

Cold email goes out from mailboxes you already have: a Google Workspace address, or an address at another email provider. You connect each one once, and Otto sends your cold campaigns from it.

Connected mailboxes are under Domains and mailboxes, in Your mailboxes at the top. In the full app that is Growth → Outreach → Cold campaigns → Domains and mailboxes; on the cold email plan it is its own entry in the menu. Only an owner or admin can connect or disconnect a mailbox.

The top of Your mailboxes says how your business sends. For most businesses, cold email goes only from the mailboxes connected there. When Otto's own sending (Amazon SES) is switched on for your business, the page says so, and your business may also send that way, from the sending domains lower on the same page.

What Otto reads, and what it leaves alone

Otto sends your cold emails from the mailbox, as that address.
Otto looks in the mailbox for replies to the cold emails it sent, and for bounce reports about them. It reads only those messages.
Everything else in the mailbox is left alone.

Google Workspace

You connect a Google Workspace address with an app password: a separate password just for Otto, which you can remove at any time.

Turn on 2-Step Verification for the Google account you send from. Google asks for it before it lets you make an app password.
Go to myaccount.google.com/apppasswords and make an app password. If Google says app passwords are not available, your Workspace admin has to allow them first.
In Otto, press Connect a mailbox and pick Google Workspace.
Type the address, paste the app password, and press Connect.

Otto signs in to Gmail's SMTP (for sending) and IMAP (for reading replies) to check that it works. Nothing is sent. If it cannot sign in, it says why, and nothing is saved. The password box is cleared once the mailbox is connected, and it is never shown again.

Another email provider

Look up your provider's SMTP server (for sending) and IMAP server (for reading). Most providers list them in their help pages, often with the ports. The usual ports are 587 for SMTP and 993 for IMAP.
Press Connect a mailbox and pick Other email provider.
Type the address, its password, the SMTP server and port, and the IMAP server and port.
Press Connect.

As with Google, Otto signs in to both to check they work, sends nothing, and says why if it cannot.

Use a mailbox in a campaign

On a draft cold campaign, your connected mailboxes are listed under Sending addresses. Tick the ones this campaign should send from. You can still type addresses yourself too.

A mailbox that is not working is marked with its problem beside it.

New addresses still warm up

A connected mailbox is a sending address like any other. When its domain is new to Otto, it starts with a few emails a day and sends a few more each day it sends. See how to warm up your sending addresses. Its warm-up and health show in the Mailboxes list on the same page.

Connecting a mailbox does not change where your emails land. That is up to each mail service.

When a mailbox shows a problem

Each mailbox shows Working, or Not working with the problem in words. While Otto cannot sign in to a mailbox, it cannot send from it or read its replies there.

Read the problem shown under the mailbox.
Fix it where your mail is kept. For example, the app password was removed, the password changed, or your admin turned off access.
Press Check again.
If it still does not work, press Disconnect, then connect it again: with a new app password for Google Workspace, or with the new password for another provider.

Disconnect a mailbox

Press Disconnect beside the mailbox and confirm. Otto stops sending from it and stops reading its replies and bounce reports.

You can also cut Otto off from your side, and it works just the same:

Google Workspace: remove the app password you made for Otto in your Google account.
Another provider: change the mailbox's password.

The next time Otto tries the mailbox, it shows Not working until you disconnect it in Otto too.