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10 min read·Beginner·6 steps·3 screenshotsGetting started

How to connect a mailbox (Google, Microsoft, your own SMTP)

Colldly sends through your own mailbox, so the email looks exactly as if it came from you. To connect it you need SMTP for sending and IMAP for collecting replies.

A mailbox is the only thing Colldly needs from you. We send from your addresses so reputation and replies belong to you. This guide shows the exact settings for Google, Microsoft and your own hosting, and what to do when the connection test fails.

Mailbox passwords are encrypted in Colldly (AES-256-GCM) with a separate key that is not stored in the database. For Google and Microsoft use an app password, not the account password.

1

Prepare the details

You need the SMTP and IMAP server addresses, ports and login details. You find them in your email provider's help, usually under "mail client settings".

colldly.com/dashboard › Email accounts
Email accounts in Colldly with the mailbox overview and SMTP test
Email accounts in Colldly with the mailbox overview and SMTP test
2

Google Workspace and Gmail

Turn on two-factor authentication and create an app password. Your normal account password will not work. The server is smtp.gmail.com on port 587 and imap.gmail.com on port 993.

Tip: The app password is shown only once. Copy it straight away; it will not appear again.
3

Microsoft 365 and Outlook

You need an app password here too. In some organisations SMTP is disabled and has to be enabled by the administrator. The server is smtp.office365.com on port 587.

4

Your own hosting

With ordinary web hosting use the details of your email account. The ports are usually 587 for SMTP and 993 for IMAP with encryption.

5

Test the connection

After saving, run the test. It verifies that the mailbox really sends and receives. Only once the test passes does it make sense to add it to a campaign.

colldly.com/dashboard › Email accounts
SMTP and IMAP connection test in Colldly
SMTP and IMAP connection test in Colldly
6

Set the signature and collector mailbox

Add a signature and choose where replies should be collected. With several sending addresses it pays to route replies into one mailbox you watch.

colldly.com/dashboard › Unibox
Collector mailboxes and Unibox in Colldly
Collector mailboxes and Unibox in Colldly
What to avoid
Using the account password instead of an app password. Google and Microsoft reject it.
Connecting your main work mailbox. Cold email belongs on a secondary domain.
Skipping the IMAP test. Without it replies never reach Unibox.
Checklist
  • You have the SMTP and IMAP host, port and an app password
  • The SMTP test (sending) and the IMAP test (receiving) passed
  • The signature is plain text with name, company and phone
  • Daily limit and gaps are set according to the mailbox's age
  • Warm-up is switched on
  • A collector mailbox is set if you rotate several addresses
Questions about this guide
Why does Google reject my password?
Gmail and Workspace do not accept the normal password over SMTP. Enable two-step verification and create an app password (16 characters); enter that in Colldly.
Can I connect dozens of mailboxes at once?
Yes, via bulk import from CSV. The system tests each one and flags the broken ones so you can fix them individually.
What does the "Broken (SMTP)" status mean?
The server refused the login: wrong password, expired app password or a changed account type. Until you fix it nothing leaves that mailbox and the campaign uses the others.
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