When Outlook stops pulling in new mail, it's usually one of four things: it's working offline, a filter is hiding the messages, the mailbox is full, or the account needs re-authenticating. Let's rule them out.
1. Check you're not in Work Offline mode
On the Send / Receive tab, look at Work Offline. If it's highlighted, click it once to go back online. This is the single most common cause.
2. Force a Send/Receive
Press F9 (or click Send/Receive All Folders). Watch the bottom-right status bar for any error — if you see one, note the error number.
3. Check your Junk, Other and Focused tabs
New mail may be landing in Junk Email, the Other tab, or being swept by a rule. Click Junk and the Other tab, and review Rules under File > Manage Rules & Alerts.
4. Make sure the mailbox isn't full
A full mailbox silently stops delivery. Log into your email through a web browser and check your storage usage. Delete large attachments or empty Deleted Items if it's near the limit.
5. Re-add the account
If a specific account stopped syncing after a password change, remove it under File > Account Settings and add it back. Outlook will re-authenticate and rebuild the connection.
6. Repair the Outlook data file
A corrupted local data file can block new mail. The built-in Inbox Repair Tool (scanpst.exe) fixes this — reach out and we'll point you to it for your exact Outlook version.