Add an Automatic Reply to a Shared Mailbox in Outlook

To add an automatic reply to a shared mailbox, open that mailbox in Outlook on the web, then go to Settings and find Automatic replies; turn them on, write the message, choose who receives it and save. If the setting is unavailable, ask your Microsoft 365 administrator to configure the reply in the Exchange admin center.

What an automatic reply does for a shared mailbox

A shared mailbox has its own email address and stores messages that several people can read or answer, such as support@contoso.com or bookings@contoso.com. An automatic reply is a mailbox-level message: it responds on behalf of the shared address, rather than sending a personal out-of-office message from each delegate’s account. This makes it useful when a team is closed, a service is temporarily unavailable or a request needs an immediate acknowledgment.

Outlook’s automatic reply feature is different from a signature, a rule that forwards mail or a manually sent acknowledgment. It is managed in Exchange, the service behind most Microsoft 365 work or school mailboxes. As a result, the setting may be easier to reach in Outlook on the web or the Exchange admin center than in the Outlook desktop app.

Before you set it up

Check that the shared mailbox exists and that you can open it. To manage its settings as a mailbox user, you generally need Full Access permission. Send As or Send on Behalf permission lets you send messages from the shared address, but by itself does not necessarily let you open the mailbox or change its automatic replies. An administrator can grant the required access.

Shared mailboxes are usually opened through a delegate’s own Microsoft 365 account; they are not normally meant to be signed into directly with a separate shared-mailbox password. If you do not see the shared mailbox, confirm the address and your access with the administrator. Permission changes can take time to appear, and signing out and back in or reopening Outlook may help after access is granted.

It is also worth agreeing on the wording and dates with the rest of the team first. A reply that promises a response time, gives a phone number or names a staff member should be accurate for the whole team, not just the person who set it up.

Set the reply in Outlook on the web

Outlook on the web is a practical option because it lets you open the shared mailbox as its own mailbox. The names of a few controls can vary as Microsoft updates the interface, but the general process is:

Sign in to Outlook on the web with your own work or school account.
Select your profile picture or initials, then choose Open another mailbox. Enter the shared mailbox address and open it. If your organization’s layout offers a shared-mailbox shortcut instead, use that to open the mailbox.
While viewing the shared mailbox, select the Settings gear. Find Automatic replies; depending on the layout, it may appear under Accounts or be easier to locate by searching Settings.
Switch on automatic replies and enter the message. If the form offers a date range, set the start and end times so the reply stops automatically when the team is back.
Choose whether to send replies only inside the organization or also to people outside it. If you enable external replies, check the available audience option, review the text, and save.

Make sure the mailbox address or name shown in Outlook is the shared mailbox, not your personal account. A useful final check is to reopen the automatic-reply settings after saving and confirm that the switch, message and dates are still correct.

Ask an administrator to configure it in Exchange

If Outlook does not show the setting, an Exchange administrator can manage it directly. In the Exchange admin center, open Recipients > Mailboxes, select the shared mailbox, and look for Others or the mailbox’s additional settings. Choose the option for managing automatic replies, enter the internal and external messages, set the schedule if needed, and save. Microsoft may adjust labels or page layout, so the exact placement can differ between admin-center versions.

This route is especially helpful when no delegate has the necessary mailbox permissions, when the team cannot open the mailbox in Outlook on the web, or when an administrator needs to apply a change centrally. It also makes clear that the setting belongs to the shared mailbox. Ask the administrator to confirm whether the rule is scheduled and whether external replies are enabled; those choices affect what customers actually receive.

For organizations that manage Exchange through administrative tools or policies, an administrator may have other ways to set mailbox-level automatic replies. Those approaches require the appropriate administrative role and should be handled by the IT team rather than by trying to sign in as the shared mailbox.

What to know about Outlook desktop

Classic Outlook for Windows has an Automatic Replies command for many Exchange accounts, but it can be confusing with a shared mailbox. The command usually controls the account currently configured in Outlook, and a shared mailbox that appears only as an additional mailbox may not have a separate Automatic Replies control in the desktop ribbon. Do not assume that changing your own account’s reply will change the shared mailbox’s reply.

If you use classic Outlook and cannot find a setting specifically associated with the shared address, open the mailbox in Outlook on the web or ask an administrator to use the Exchange admin center. New Outlook for Windows has a different settings interface, and available controls can depend on how the shared mailbox was added and on your organization’s configuration. Opening the mailbox separately in Outlook on the web is a useful way to verify that you are working on the right mailbox.

Outlook for Mac also has its own account settings and may not expose the shared mailbox’s automatic-reply controls in the same way as Outlook on the web. The reliable principle across desktop versions is to confirm which mailbox the setting applies to before saving. If the shared address is not explicitly selected, use the web or admin-center method instead.

Choose message, audience and schedule carefully

A useful reply states what the sender can expect, without suggesting that a person has read the message if nobody is monitoring the mailbox. For example: “Thank you for contacting the service desk. Our office is closed on Monday, 18 May. We will review your message when we reopen on Tuesday. For urgent account-access issues, use the support portal.” Replace the dates and instructions with information that is actually valid for your organization.

Internal replies: These go to people in your organization. Use them to tell colleagues who is covering the mailbox or where to route urgent requests.
External replies: These go to people outside your organization. Keep the message suitable for customers, suppliers and other unknown senders.
External audience: If Outlook offers a choice between contacts only and all external senders, select the narrower option when it meets the need. A broad setting may reply to unsolicited mail as well as legitimate requests.
Schedule: Set a start and end time when the absence or closure has a known duration. Check the time zone and confirm whether the end time should include the first day the team is open.

Automatic replies are not a substitute for a monitored inbox. They do not assign an employee to handle a request, guarantee delivery of the sender’s message or tell the sender that a case has been created. If the mailbox is used for urgent work, include a real monitored alternative and make sure that route is staffed.

Common problems and how to fix them

The setting is missing: Make sure you opened the shared mailbox itself, rather than its folder within your personal mailbox. If the setting still is not available, ask an administrator to check Full Access and configure the reply in Exchange.
The reply comes from your own address: You probably changed your personal account’s automatic replies. Reopen the shared mailbox separately and verify the mailbox identity before editing the setting.
External senders receive nothing: Check that external replies are enabled and that the selected audience includes that sender. Some organizations restrict external automatic replies through policy.
The message did not stop on the expected day: Review whether a date range was enabled, confirm its end time and time zone, and save the updated settings. If the reply was configured without an end time, turn it off manually when it is no longer needed.
People get unexpected or duplicate replies: Check whether more than one mailbox or automated system is responding. A separate rule, ticketing platform or forwarding workflow could send another acknowledgment. Ask the administrator to review the mailbox configuration if the source is unclear.

Automatic replies commonly send a response once to a particular sender during an active reply period, rather than repeating it for every message that person sends. This is why sending a test message repeatedly from one address may not produce a fresh reply every time. Test from a separate address if appropriate, and avoid testing with sensitive or customer information.

Security and licensing considerations

Keep the message brief and avoid including confidential details, personal data, internal schedules or information that would help someone target staff. External automatic replies can disclose that an address is active and may be sent to unsolicited senders, so consider whether external replies are necessary and whether limiting them to contacts is sufficient. Do not put passwords, access codes or private case details in an automatic response.

Turning on automatic replies does not normally create a separate charge by itself. Shared-mailbox licensing depends on the organization’s Microsoft 365 plan and how the mailbox is used; for example, storage capacity and advanced features can affect licensing requirements. An administrator should check current Microsoft licensing terms rather than assuming every shared mailbox is covered in every situation.

Frequently Asked Questions

Can I set an automatic reply for a shared mailbox without being an administrator?
Often, yes, if you have the permissions needed to open and manage the shared mailbox. If Outlook does not expose the setting or you lack Full Access, an Exchange administrator can configure it.

Will the reply come from the shared email address?
When configured on the shared mailbox, the automatic reply is associated with that mailbox, not your personal out-of-office message. Confirm the mailbox name while editing so you do not change your own account by mistake.

Can a shared mailbox send automatic replies to external customers?
Yes, if external replies are enabled and your organization’s settings allow them. You may be able to limit replies to external contacts; use that option if replying to every outside sender is not appropriate.

Can I set different replies for internal and external senders?
Exchange automatic-reply settings can provide separate internal and external message fields. Use the internal version for colleague-specific instructions and keep the external version appropriate for customers and other outside senders.

Why does the shared mailbox not appear when I choose Open another mailbox?
Check that you entered the correct email address and that an administrator has granted you access. If permission was recently added, allow time for it to take effect, then try again or ask the administrator to confirm access.

Does an automatic reply forward or answer every message?
No. It sends a preset acknowledgment according to the mailbox’s automatic-reply settings; it does not forward the message, create a support ticket or ensure that someone handles the request. Set up separate routing or monitoring if the team needs those functions.

Try it: the Date Difference Calculator: days, months, years and weekdays between two dates, with the DATEDIF formulas.

More in How-to basics

Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

Spotted an error in this guide? Let us know.