Workspace Mailboxes, Gmail OAuth and Campaign Sending
A guide to ScaleBlogger workspace mailboxes: unified sending and receiving identities, Gmail OAuth, and campaign mailbox selection and rotation.
Workspace Mailboxes, Gmail OAuth and Campaign Sending
ScaleBlogger now uses one mailbox layer, workspace_mailboxes, for both Outreach sequences and Email Marketing campaigns. You can manage sending and receiving identities, connect a Gmail account through OAuth, and choose which mailbox a campaign sends from, including rotating across a pool.
Where to find it
- Settings → Mailboxes — add, edit, and delete mailboxes and verified sending domains.
- Marketing → Email Campaigns → New — on the Sending Mailbox step, pick one mailbox or a rotating pool.
Supported mailbox providers
| Provider | How it is added | Best for |
|---|---|---|
| Smartlead | API key in Settings → Mailboxes | Outreach sending |
| Instantly | API key in Settings → Mailboxes | Outreach sending |
| SMTP | Host, username, password | Any email host |
| IMAP | Host, username, password | Reply polling only |
| Gmail | Connect Gmail OAuth button | Gmail/Google Workspace |
| Outlook | OAuth or manual setup | Microsoft 365/Outlook |
| Resend | Verified sending domain | Marketing newsletters |
Adding a mailbox
- Open Settings → Mailboxes.
- Click New mailbox.
- Choose the provider and enter the required credentials.
- Set a daily limit. The default is 50.
- Toggle Default mailbox if this should be the website fallback.
- Choose an inbound method: none, IMAP polling, Resend inbound, or manual forwarding.
- Save.
Connecting Gmail
- In Settings → Mailboxes, click Connect Gmail.
- Sign in to the Google account you want to send from.
- Allow the requested mail, profile, and email scopes.
- When the popup closes, the mailbox appears with provider gmail and pre-filled SMTP/IMAP settings.
Google may not return a new refresh token if you already granted access; ScaleBlogger preserves the existing refresh token when reconnecting.
Choosing a campaign mailbox
When you create an Email Marketing campaign and reach the Sending Mailbox step:
- Select one mailbox to send from a specific identity.
- Select two or more mailboxes to rotate. If none are selected, the campaign uses the website default active mailbox.
- With multiple mailboxes, choose a rotation strategy:
- Round-robin — cycles through the pool in stable order.
- Least used — picks the mailbox with the most remaining daily headroom.
The campaign scheduler records which mailbox sends each recipient so delivery reporting stays accurate.
Common issues
- No active mailbox available — add a mailbox in Settings → Mailboxes and set its status to active. Campaign selection only shows resend, smtp, gmail, and outlook providers.
- Gmail connection fails — make sure popups are allowed, the Google OAuth client is configured, and you approve the mail.google.com scope.
- Emails not sending — check that a website is selected, the chosen mailbox is active and under its daily limit, and the mailbox health is not critical.
- Rotation feels uneven — paused, unhealthy, or daily-limit-exhausted mailboxes are skipped. Least-used balances against each mailbox daily limit.