email not coming in unless i close and open outlook

Hi,

Since the messages appear after you close and reopen new Outlook, this may be related to the Outlook app not refreshing the mailbox correctly rather than the messages not being delivered.

Could you please try the following checks:

1/ When the issue happens again, open Outlook on the web and check whether the new message is already there.

• If the message appears on the web but not in new Outlook, that would point more toward a local synchronization issue with the new Outlook app.
• If it is also missing from Outlook on the web, the issue may be related to mail delivery rather than the Outlook app itself.

2/ Before closing Outlook, try forcing a sync: Go to View > Sync, or press F9.

Microsoft documents this as the manual way to check for new mail in new Outlook: Sync to manually check for new mail and to send messages in Outlook | Microsoft Support

3/ If Sync does not bring in the messages, try repairing new Outlook from Windows:

• Settings > Apps > Installed apps
• Locate Outlook (new)
• Select Advanced options, if available
• Try Repair first.

Reference: Repair apps and programs in Windows | Microsoft Support

4/ If the issue continues, you can also remove and add the affected account again in new Outlook:

• View > View settings > Accounts > Your accounts
• Select Manage next to the affected account > Remove
• Then add the account again.

Microsoft documents the account removal steps here: Add an email account to Outlook for Windows | Microsoft Support

Please also let me know:

• Is this happening with your primary Microsoft 365 mailbox or a shared mailbox?
• When the problem occurs, does View > Sync/F9 immediately bring the missing emails in?
• Are the emails already visible in Outlook on the web at that time?

These details will help narrow down whether the issue is with mailbox delivery or the new Outlook synchronization session.