Outlook not connecting to server: solutions and fixes

Outlook not connecting to the server? Suddenly you see "Disconnected" or "Working Offline" at the bottom of Outlook, and no new emails are coming in. In most cases it's not the mail server itself, but a setting, an expired password or a corrupted data file. Work through these solutions from top to bottom, from the quickest check to the most thorough repair.

The status bar at the bottom of Outlook tells you what's wrong

First look at the status bar at the bottom right of the Outlook window. The text there often reveals the cause immediately.

Status message	Meaning
Connected	Everything is working; the problem lies elsewhere
Working Offline	The Work Offline button is on; click it to turn off
Disconnected	No connection to the server, often network or profile
Connecting / Updating	Outlook is trying to connect; wait a moment
Need Password	Sign-in details have expired or are incorrect

These messages point you to the right solution below. At the same time, test whether other programmes have internet access, so you can immediately rule out a network outage. If your email does work in your provider’s webmail but not in Outlook, then the problem is in the Outlook installation or the profile, not the server.

Always start with the simplest action: close Outlook completely and restart it. A restart puts an end to temporary glitches, for example after waking from sleep mode or after a brief network interruption. If the status bar still shows an error after that, work through the steps below in order; the first take seconds, the last are more thorough.

Turning off Work Offline is the first check

The most common cause is the Work Offline button accidentally being on. Outlook is then still connected to the internet, but deliberately doesn’t fetch mail.

1. Go to the Send/Receive tab on the ribbon.
2. Look at the Work Offline button on the right. If it’s highlighted (pressed), the offline mode is on.
3. Click the button once to go back online. The status bar should now switch to Connected.

If Outlook remains offline after you’ve turned off the button, close the programme completely and restart it. Sometimes the switch gets stuck due to a temporary glitch.

The connection status reveals whether the server is reachable

If you want to see whether Outlook actually reaches the server, open the Connection Status window.

1. Hold down Ctrl and right-click the Outlook icon in the system tray, next to the clock.
2. Choose Connection Status from the menu.
3. Look at the Status column. If all lines say Connected, the server connection is fine. If you see Disconnected or Reconnecting, the problem is in the network or the profile.

This window is especially useful for an Exchange or Microsoft 365 account, because you see the individual connections (folder, username, protocol) separately. If you don’t see the icon in the system tray, first click the arrow that shows hidden icons.

Rule out network and server status first

Before you start tinkering with your profile, check that the path to the server is clear.

• Test your internet. Open a website or ping a well-known server from the command prompt with ping 8.8.8.8. If you get no response, it's the network, not Outlook.
• Check the service status. If you use Microsoft 365, see if Microsoft is reporting an outage. In a large-scale outage, no local solution helps and you can only wait.
• Check the firewall or VPN. A VPN or strict corporate firewall can block the connection to the mail server. Temporarily disable the VPN to test this.

If webmail does work, you know for sure that the server is running and your login details are correct. The rest of this guide then focuses on the Outlook client on your computer.

If you often switch locations, also think about the network itself. A guest network in a hotel or at the office sometimes blocks the ports that email uses, while ordinary websites load fine. In that case, test with a mobile hotspot: if Outlook connects via the hotspot, the limitation is with the original network and not with your settings.

An expired password silently breaks the connection

If the message "Need Password" appears or Outlook keeps asking you to sign in, the saved sign-in details are outdated. Remove them so Outlook can log in again.

1. Close Outlook.
2. Open Control Panel and go to Credential Manager > Windows Credentials.
3. Find the entries that start with MicrosoftOffice or Outlook and remove them.
4. Restart Outlook. The programme will now ask for your password again; enter the correct one.

If you work with a business Microsoft 365 account with two-step verification, you may also need to confirm the login via the authenticator app after entering the password. If the login still hangs, it helps to remove the account and add it again.

Use the repair tool to fix a faltering account

Outlook has a built-in feature to check and restore account settings.

1. Go to File > Account Settings > Account Settings.
2. On the Email tab, select the account that isn’t working.
3. Click Repair and follow the prompts. Outlook checks the server settings and adjusts them where necessary.
4. Restart Outlook once the repair is complete.

If that doesn’t work, create a new Outlook profile via the Control Panel under Mail (Microsoft Outlook) > Show Profiles > Add. A damaged profile is a common but easily overlooked cause.

Rebuild a damaged OST file

With an Exchange or Microsoft 365 account, Outlook keeps an offline copy of your mailbox in an .ost file. If that gets corrupted, the connection hangs. Because it’s only a copy, you can safely have it rebuilt.

1. Close Outlook completely.
2. Open the folder containing the file by pasting the path into File Explorer:

%localappdata%\Microsoft\Outlook

3. Rename the file with the .ost extension, for example to old.ost.bak. You may also delete it.
4. Restart Outlook. The programme downloads your mailbox again from the server and creates a fresh .ost file.

If you use a POP or IMAP account with a local .pst file, don’t delete it, because that holds your only copy. Instead repair a .pst with the Inbox Repair Tool SCANPST.EXE, which is in the Office installation folder. In the tool, browse to the .pst file, click Start and then Repair; run it several times if needed until no more errors are found.

Cached Exchange Mode determines how Outlook talks to the server

With an Exchange or Microsoft 365 account, Outlook works in cached mode by default: it keeps a local copy in the OST file and synchronises that with the server. If there is a glitch there, Outlook appears connected but synchronisation gets stuck.

1. Go to File > Account Settings > Account Settings.
2. Double-click your account and look at the option Use Cached Exchange Mode.
3. Turn it off temporarily to test whether Outlook maintains a connection directly to the server. If that works, the OST file was the culprit.
4. Then turn cached mode back on and rebuild the OST file as described above.

Keep cached mode on for everyday use; it makes Outlook faster and lets you continue working during a brief network interruption.

Safe mode points out a disruptive add-in

A faulty add-in can sabotage the connection. Test this with safe mode.

1. Press Windows key + R, type the following command and press Enter:

outlook /safe

2. Outlook now starts without add-ins. If the connection now holds, an add-in is the cause.
3. Close, start normally and go to File > Options > Add-ins.
4. At the bottom under Manage, choose COM Add-ins and click Go. Disable the add-ins one by one until you find the troublesome one.

If you only want to restore the navigation pane because folders aren’t loading, use the command outlook /resetnavpane.

Antivirus and security can block the mail connection

Some antivirus programmes scan incoming and outgoing email and position themselves between Outlook and the server for that purpose. If that goes wrong, the connection can hang while your network is otherwise working fine.

• Temporarily disable the email protection or SSL scanning of your antivirus and see if Outlook then connects.
• Check whether port 993 (IMAP) or 995 (POP) and 587 (SMTP) are not blocked by the firewall for an account that does not use Exchange.
• If you work on a corporate network, ask the administrator whether a proxy or content filter is blocking the connection to the mail server.

Always turn security software you have disabled back on once you have completed the test, so your computer remains protected.

An Office repair fixes a damaged installation

If the problem persists after all the above steps, the Office installation itself may be damaged. Repair it via Windows.

1. Open Settings > Apps > Installed apps (or Programmes and Features in the Control Panel).
2. Find Microsoft 365 or Microsoft Office, click the three dots and choose Modify.
3. First choose Quick Repair; that works offline and takes little time. If that doesn’t solve anything, choose Online Repair, which renews the installation.

Close all Office programmes before you start, because the repair restarts them. An online repair can take fifteen minutes or longer depending on your internet connection, because Windows partly fetches the installation again. So allow some time for this and save open work in other programmes before you start it.

The new Outlook works differently from the classic version

Since Microsoft has been rolling out the new Outlook, the distinction is important. The new Outlook (recognisable by the switch in the top right) uses no .ost or .pst files and has no Work Offline button or the outlook /safe command. You solve connection problems there differently.

• Check your account via Settings > Accounts and remove and re-add the account if it isn’t synchronising.
• Temporarily switch off the New Outlook toggle to return to the classic version, where the above steps do apply.

After rebuilding your mailbox, Outlook must re-index everything; if searching then stutters, read how to repair the Outlook search function. If the problem arose after a reinstallation with the wrong licence, look at the difference between OEM, retail and volume licences. The official explanation of offline mode can be found in Microsoft support.