Microsoft outlook stopped working

Since reinstalling Outlook and Microsoft 365 did not fix it, focus on connection state, server access, and Outlook cache/account reset.

1. Verify Outlook is not offline.
   • In Outlook for Mac, open the Outlook menu.
   • Make sure Work Offline is not checked.
2. Confirm the Mac still has network access.
   • Open a web browser and verify normal internet access.
   • If this is on a local network, also verify access to internal network resources if the mail server is internal.
3. Check the account connection status in Outlook.
   • Go to Tools > Accounts.
   • Select the Exchange account in the left pane.
   • If the connection indicator is orange, Outlook is not connecting properly to the server.
   • If the account worked before, test the same mailbox in Outlook on the web. If web access works, the issue is likely local to Outlook on the Mac.
4. Reset the account in Outlook for Mac.
   • This is the best next step after reinstall attempts failed.
   • Warning: resetting the account deletes any information that is not synchronized with the server.
   • Make sure the Mac is connected to the server.
   • In Outlook, go to Tools > Accounts.
   • Select the affected account.
   • At the bottom, select Manage > Reset Account.
   • This forces Outlook to re-sync the affected items from the server.
5. If only specific folders are affected, empty the cache for that Exchange folder.
   • Warning: this deletes any information in that folder that is not synchronized with the Exchange server, including contacts' mail certificates.
   • In the navigation pane, Ctrl+click or right-click the Exchange folder.
   • Select Properties.
   • On the General tab, choose Empty Cache.
   • Outlook will download the latest items from the Exchange server again.
6. If the account is POP or IMAP rather than Exchange, verify outgoing server settings.
   • Go to Tools > Accounts.
   • Select the account.
   • Under Outgoing server, choose More Options.
   • Turn on the required SMTP authentication type and enter credentials if needed.
   • Also verify the email address, user name, password, server name, and any required SSL or custom port settings.
7. Check for known Outlook for Mac issues.
   • If Conditional Access is enabled in the environment, Outlook for Mac sync issues were fixed in 16.92 (Build 24120731).
   • If Outlook crashes during sync or startup, that was fixed in 16.47 or later.
8. If the server account still cannot be added after reset and settings verification:
   • Check whether the mail server is available.
   • If this is an Exchange account, contact the Exchange server administrator to confirm server health and account access.
   • If this is a POP/IMAP account, confirm with the email provider that the correct server settings are being used and whether a firewall or proxy is blocking SMTP or mail server access.

Reinstalling alone would not correct a corrupted local cache, incorrect account settings, server unavailability, or a server-side access issue. The most relevant next actions are Reset Account, Empty Cache for affected folders, and verifying whether the mailbox works in Outlook on the web.

References:

• I'm not receiving email or other items in my Exchange account in Outlook for Mac
• Clear the cache in Outlook for Mac
• I can't send or receive messages with Outlook for Mac
• Outlook for Mac stops syncing when Conditional Access is enabled
• Outlook for Mac crashes unexpectedly on startup or during mail synchronization