What is a Shared Mailbox?

A shared mailbox is an email address that multiple people in your team can send and receive from, like info@company.com.au, accounts@company.com.au, or reception@company.com.au. Unlike a personal mailbox, nobody "owns" a shared mailbox — the whole team shares access to it.

Setting up automatic replies on a shared mailbox is useful when:

Your office is closed for a public holiday
The team that monitors the mailbox is unavailable
You want to acknowledge incoming enquiries immediately (e.g., "We have received your message and will respond within 24 hours")

Setting Up Automatic Replies via Outlook Web

This is the simplest method and does not require administrator access.

Step 1: Open the Shared Mailbox in Outlook Web

Go to outlook.office.com and sign in with your work account
Click your profile picture or initials in the top-right corner
Click Open another mailbox
Type the shared mailbox email address (e.g., info@company.com.au)
Click Open

The shared mailbox will open in a new browser tab.

Step 2: Open Automatic Replies Settings

In the shared mailbox tab, click the Settings gear icon in the top-right
Search for Automatic replies in the settings search bar
Click Automatic replies

Step 3: Configure Your Reply

Toggle Turn on automatic replies
Optional: Set a time range by ticking Send replies only during a time period and selecting start and end dates
Type your message in the Inside my organisation box

Example message for inside your organisation:

Thank you for your email to the info inbox. Our team is currently out of the office for the [holiday name] public holiday. We will respond to your message on [date].

If your matter is urgent, please call 1300 521 162.

If you want people outside your organisation to receive a reply, tick Send replies outside my organisation
Select Send to all external senders (recommended for general enquiry mailboxes)
Type your external message

Example message for external senders:

Thank you for contacting [Company Name]. We have received your email and will respond within one business day.

If you need immediate assistance, please call 1300 521 162 during business hours (Monday to Friday, 8:30am to 5:00pm AEST).

Click Save

Step 4: Verify

Send a test email to the shared mailbox from a different email address to confirm the automatic reply is working.

Setting Up Automatic Replies via Microsoft 365 Admin Centre

If you are a Microsoft 365 administrator, you can set automatic replies for any shared mailbox.

Step 1: Open the Admin Centre

Go to admin.microsoft.com
Sign in with your admin account

Step 2: Find the Shared Mailbox

Click Teams & groups > Shared mailboxes
Click the shared mailbox you want to configure

Step 3: Open Exchange Admin Centre

Click Manage mail flow settings
This opens the Exchange admin centre for that mailbox
Click Manage automatic replies
Configure the same settings as described above

Setting Up Automatic Replies via Exchange Online PowerShell

For IT administrators who prefer command-line tools:

``` Set-MailboxAutoReplyConfiguration -Identity "info@company.com.au" -AutoReplyState Enabled -InternalMessage "Thank you for your email. Our team is currently unavailable." -ExternalMessage "Thank you for contacting us. We will respond within one business day." -ExternalAudience All ```

To disable:

``` Set-MailboxAutoReplyConfiguration -Identity "info@company.com.au" -AutoReplyState Disabled ```

Tips for Shared Mailbox Automatic Replies

Be specific about when you will respond. Instead of "We will get back to you soon", say "We will respond within one business day" or "We will reply when we reopen on [date]."

Include alternative contact options. Provide a phone number or alternative email for urgent matters.

Use a professional tone. The shared mailbox represents your business, not an individual.

Set a time range. If the automatic reply is for a holiday or specific event, set an end date so it turns off automatically.

Check it is working. Send a test email to the shared mailbox after setting up the reply.

Remember to turn it off. If you did not set an end date, remember to disable the automatic reply when your team returns.

Automatic Acknowledgement Messages

Some businesses keep automatic replies permanently enabled on shared mailboxes to acknowledge every incoming email. This works well for:

General enquiry mailboxes (info@, enquiries@)
Support mailboxes (support@, helpdesk@)
Feedback mailboxes (feedback@)

Example permanent acknowledgement:

Thank you for your email. Your message has been received and our team will review it promptly.

For urgent matters, please call 1300 521 162.

Note: Microsoft 365 sends automatic replies only once per sender in a given session (usually within a few hours). This prevents the same person from receiving multiple auto-replies if they send several emails in quick succession.

Troubleshooting

Automatic reply not being sent

Verify the automatic reply is enabled (check the toggle)
Make sure the time range (if set) covers the current date
External replies may be disabled by your organisation's mail flow rules — check with your IT administrator
Send a test email from an account that has not already received the auto-reply today

Cannot access automatic reply settings

You need "Full Access" permission on the shared mailbox to change its settings
Ask your IT administrator to grant you Full Access, or ask them to set up the reply for you

Reply only going to internal senders

Check that "Send replies outside my organisation" is ticked
Ensure "Send to all external senders" is selected (not just contacts)

Need Help?

For help configuring shared mailbox settings, contact helpdesk@netlumait.com.au or call 1300 521 162.

How to Set Up Automatic Replies for a Shared Mailbox