How to connect Google Workspace inboxes to Instantly, Smartlead or PlusVibe

Google retired plain password sign-in for third-party apps, the old "less secure apps" switch. A sequencer now reaches a Google Workspace inbox in one of two ways: OAuth, where you sign in through Google and approve access, or an app password, a 16-character password used over IMAP and SMTP. Both work. Each one is blocked by a different setting until somebody changes it.

Should you connect with OAuth or an app password?

Use OAuth when you can sign in to each account and the sequencer is trusted in the Workspace Admin console. Use an app password when you are connecting many accounts from a CSV, or OAuth is blocked by policy you cannot change. Sequencers generally recommend OAuth because it survives password changes; app passwords are what bulk imports use.

Connecting with OAuth

In the sequencer, choose to add a Google or Gmail account, sign in as the inbox, and approve the permissions. If the Workspace restricts third-party apps, Google stops you with an Access blocked page saying the administrator needs to review the app, and an error of admin_policy_enforced.

The fix is on the Workspace side, not the sequencer. In the Admin console, open Security, Access and data control, API controls, Manage third-party app access, and add the sequencer’s app as Trusted using the client ID from the sequencer’s own help page. It is a one-time change per Workspace, after which every account in it can connect.

1. Find the sequencer’s Google client ID in its help docs (Instantly, Smartlead and PlusVibe each publish one).
2. Admin console: Security, Access and data control, API controls, Manage third-party app access.
3. Configure new app, search by the client ID, select it, and set access to Trusted.
4. Return to the sequencer and connect each account again.

Connecting with an app password

Turn on 2-Step Verification for the account, then create an app password at myaccount.google.com/apppasswords. Google shows it once, as 16 characters. Use the full email address as the username and the app password, not the account password, in both the IMAP and SMTP settings.

If the App passwords page says the setting is not available, 2-Step Verification is either off for the account or not allowed by the Workspace. The administrator has to let users turn it on before anyone can create an app password.

What do the Google sign-in errors mean?

Settings to change once the inbox is connected

Connecting is not the same as being ready to send. Set each inbox’s daily campaign limit to what it is sized for, turn on warm-up, and set a custom tracking domain if you track opens or clicks, so the links in your mail do not point at a domain shared with every other user of the sequencer.

• Daily campaign limit: we size a Google inbox for 15 a day, ramped up to rather than started at.
• Warm-up: about 20 sends a day per inbox, running before and alongside campaigns.
• Sending window and gaps between sends, so three inboxes on one domain do not fire together.
• Custom tracking domain, a CNAME on the sending domain, if tracking is on at all.

The reasoning behind those numbers is in Gmail sending limits for cold email.

Connecting Google inboxes bought from us

A Google order from coldemailinboxes.io arrives as an accounts CSV on your dashboard: each address and its sign-in details, with SPF, DKIM and DMARC already verified on the domain. We never send passwords by email; the email only tells you the file is ready. Full admin access, including the Admin console, is part of the order, so you can do any step above that needs it yourself. If a connection is refused, write to info@coldemailinboxes.io with the error and the address.