🚫 What This Error Means

If you see User is authenticated but not connected when connecting a Microsoft email account in Mailbird Next, it means Microsoft accepted the sign-in, but then refused to open the mailbox connection.

In other words, your username, password, and Microsoft OAuth sign-in were correct, but the Microsoft IMAP email server still refuses access to the mailbox data.

⚠️This is a known Microsoft-side IMAP/OAuth problem that can also appear in other email clients, not only Mailbird Next.

This most often affects accounts that are connected through IMAP, such as:

• Outlook.com
• Hotmail
• Live
• MSN
• Microsoft 365 accounts using IMAP

🔍 Why This Happens

The most common cause is that Microsoft is temporarily refusing new IMAP mailbox sessions after the account has too many active connections. This can happen if the same mailbox is being used in several places at once, such as:

• Mailbird Next
• Outlook on the web
• Outlook desktop or mobile apps
• Phone or tablet mail apps
• Other desktop email clients

When this happens, Microsoft may apply a temporary connection limit or cooldown period. The most recently added app is often the one that shows the error, even though that app did not cause the underlying Microsoft-side limit.

Microsoft also notes that Outlook.com requires OAuth2 / Modern Auth for IMAP and that POP or IMAP access may need to be enabled manually in Outlook.com settings before another email app can connect to the mailbox.

🔧 Step 1: Reduce Connections in Mailbird Next

Start by reducing how many simultaneous IMAP connections Mailbird Next uses for the affected Microsoft account.

1. Open Mailbird Next.
2. Click the Settings icon, which is the gear icon on the left-hand side.
3. Go to the Accounts tab.
4. Select the affected Outlook, Hotmail, Live, MSN, or Microsoft 365 account.
5. Click the Settings tab at the top of the account menu.
6. Set Maximum connections to 2. If the problem continues, try 1.
7. Click Save.

If you use the same mailbox in other email apps, reduce their connection count as well where possible. Ideally, each app should use only one connection while this issue is being resolved.

⏳ Step 2: Wait for Microsoft's Cooldown Period

If Microsoft has already throttled the account, the change may not take effect immediately.

After reducing connections, we recommend that you:

• Close other mail apps that use the same Microsoft account.
• Keep Mailbird Next set to 1 or 2 maximum connections.
• Wait 2-6 hours.
• Then reopen Mailbird Next and check whether the account reconnects.

In many cases, the error clears only after Microsoft releases the temporary connection block.

📬 Step 3: Make Sure IMAP Is Enabled in Outlook.com

If this is a personal Outlook.com, Hotmail, Live, or MSN account, confirm that IMAP access is enabled in Outlook on the web.

1. Sign in at https://outlook.live.com from a desktop browser.
2. Open Settings.
3. Go to Mail > Forwarding and IMAP.
4. Turn on Let devices and apps use IMAP.
5. Save the change.
6. Try reconnecting or syncing the account in Mailbird Next again.

Microsoft states that POP and IMAP access will likely be disabled by default, so this step is especially important for personal Microsoft email accounts.

✅ Step 4: Approve the Sign-In in Microsoft Recent Activity

Microsoft may sometimes block or hold an IMAP connection until you confirm that the sign-in attempt was legitimate.

1. Go to https://account.live.com/activity.
2. Sign in with the affected Microsoft email address.
3. Look for a recent session that matches the time when Mailbird Next showed the connection error.
4. Expand the entry and select This was me, if that option is shown.
5. Try connecting the account in Mailbird Next again.

🏢 If This Is a Microsoft 365 Work or School Account

If the account belongs to a company, school, or organization, the mailbox administrator may need to check whether IMAP access is allowed for your mailbox.

Please ask your Microsoft 365 administrator to confirm that:

• IMAP is enabled for the mailbox.
• Modern Authentication / OAuth2 is allowed.
• No policy is blocking third-party IMAP clients (such as Mailbird Next).

If your Mailbird Next plan supports Exchange (i.e. Premium license) connecting the account through Exchange instead of IMAP is often the better option for Microsoft 365 mailboxes.

🌐 If It Still Does Not Work

If the error continues after completing the steps above, try the following:

• Temporarily disable any VPN and try again.
• Temporarily disable antivirus email scanning and try again.
• Try a different network connection.
• Remove the account from Mailbird Next and add it again, making sure to approve the Microsoft OAuth sign-in when prompted.

These steps are secondary checks. In most confirmed cases, the main issue is Microsoft accepting authentication but refusing the IMAP mailbox connection because of IMAP access settings or temporary connection throttling on their side.

🤝 Need More Help?

We may be unable to provide further assistance with this issue, as it stems from Microsoft's email server architecture. However, if you have already tried the steps outlined above and the error persists, we can take a closer look to confirm whether it is indeed related to this known Microsoft issue. 

When contacting us, please include a copy of your log file with your message. Click here for instructions on how to retrieve your log file.