Table of Contents
What This Feature Does #
A Reply-To Mailbox is an IMAP, POP3, or OAuth inbox configured so that campaign replies and direct contact emails flow to a specific user. Each mailbox is assigned to one user — only that user can see and respond to emails in that mailbox.
When to Use #
- Use when you want campaign recipients to be able to reply to your campaigns.
- Use when a specific agent handles email conversations for certain contacts.
- Do not use this for sending bulk campaigns — that is the Outbound Mail Server.
Prerequisites #
- CompanyAdmin role (to configure).
- TenantUser role (to use — as the assigned user).
- Pro plan.
- Inbound mailbox credentials (IMAP/POP3) or OAuth authorization (Gmail, Outlook).
10.2.1 Supported Mailbox Types #
IMAP (standard)
- Any email provider that supports IMAP
- Typical host examples:
imap.gmail.com,imap.outlook.com,mail.yourprovider.com - Port: 993 (SSL) or 143 (STARTTLS)
POP3 (standard)
- Any provider that supports POP3
- Typical host:
pop.gmail.com,pop.yourprovider.com - Port: 995 (SSL)
Gmail OAuth
- No password required
- Click Connect with Google and authorize the Gmail mailbox
- Application uses OAuth 2.0 to access the inbox securely
Outlook OAuth
- No password required
- Click Connect with Microsoft and authorize
- Uses OAuth 2.0; works with Microsoft 365 and Outlook.com accounts
10.2.2 Add a Reply-To Mailbox #
- In the sidebar, click Email → Mailboxes.
- Click Add Reply-To Mailbox.
- Fill in the Inbound Settings section:
- Provider: IMAP, POP3, Gmail OAuth, or Outlook OAuth
- Host, Port, Username, Password (for IMAP/POP3)
- Or: click Connect with Google / Microsoft (for OAuth)
- Fill in the optional Outbound SMTP section (for sending replies):
- If left blank, replies use Gmail/Outlook OAuth channel natively.
- For IMAP/POP3: provide SMTP host, port, username, password.
- Set the Display Name and Reply-To Email address shown to recipients.
- Choose the Assigned User (the user who will see this mailbox’s emails).
- Click Save.
10.2.3 Test the Mailbox Connection #
- After saving (or while creating), click Test Inbound Connection.
- Application attempts to connect using the provided credentials.
- Click Test Outbound Connection to verify SMTP settings.
Messages:
- Success feedback shown in the connection test result area.
- Error details shown if connection fails (e.g., wrong password, incorrect host, SSL mismatch).
10.2.4 Assign or Reassign a Mailbox #
- Only CompanyAdmin can assign a mailbox to a user.
- Go to Edit Reply-To Mailbox and change the Assigned User dropdown.
- The new assignee immediately starts seeing incoming emails in their Email Conversations view.
10.2.5 Mailbox Health Warnings and Paused Sync #
Application monitors Reply-To Mailboxes during automatic inbox sync. If a mailbox cannot authenticate, the system retries automatically up to three times for that mailbox.
If the mailbox still cannot connect after the third authentication failure:
- the mailbox row shows a warning state such as Sync warning (1/3, 2/3) while retries are still in progress, or Sync paused after the retry cap is reached
- the most recent sync error and time are shown on the mailbox row
- CompanyAdmin users receive a notification in the Notification Bell dropdown and All Notifications page
- the Email menu in the left navigation can show a warning badge so the issue is visible without opening the mailboxes page
How the warning clears:
- a successful Test Inbound Connection or successful mailbox validation clears the warning
- a later successful background inbox sync also clears the warning automatically
- after recovery, the mailbox warning notification is removed from active notifications
Errors, Messages, and Common Fixes #
| Message | Why It Happens | How to Fix |
|---|---|---|
Mailbox not found. | Deleted or access denied | Reload the mailboxes list |
Could not create/update mailbox. | Validation or server error | Check all required fields |
| Connection test failed | Wrong host, port, or credentials | Verify credentials in your email provider’s settings |
Gmail OAuth: Access denied | Gmail security blocks app | Enable Less Secure App Access (deprecated) or use Google OAuth flow |
Outlook OAuth: AADSTS error | Microsoft tenant policy restriction | Ask IT admin to grant OAuth app consent |
Sync warning (1/3) or Sync warning (2/3) | Automatic inbox sync failed to authenticate and is retrying | Verify credentials, OAuth grant, host, port, and SSL/TLS settings before the mailbox reaches the pause limit |
Sync paused | The mailbox failed to authenticate 3 times and automatic inbox sync has been paused | Open the mailbox, correct the configuration, and run Test Inbound Connection or save a working OAuth reconnection |
Best Practices #
- Use OAuth for Gmail and Outlook — it is more secure and reliable than password-based IMAP.
- Create one Reply-To Mailbox per agent when each agent has their own customer base.
- If you have one shared inbox, assign it to a team lead who coordinates responses.
- Match the Reply-To email address to the actual mailbox address to avoid confusion.
- Treat Sync warning badges as early warning signs. Fix the mailbox before it reaches Sync paused so inbox replies keep flowing without interruption.
