Apple Mail Not Receiving Emails on Mac: 3 Fixes in Order

Mac Mail not working usually looks like one of four things: you are not receiving emails on your Mac while webmail shows them, an account shows a lightning bolt or warning icon in the sidebar, the status bar says "Checking for mail" and never finishes, or email on your Mac stops updating for one account only. All four mean the same thing underneath: Mail cannot hold a working connection to the mail server.

Messages are safe in the meantime, because the server keeps receiving them. They reach Mail once it can sign in and connect again. Use the table to jump to the right fix. Fix 1 takes ten seconds, Fix 2 handles rejected sign-ins, and Fix 3 uses Connection Doctor to find a silent failure.

Why does Mac Mail say Offline?#

Apple says an account can be offline when your internet connection is disrupted, a mail server has problems, or you deliberately took the account offline. Mail shows this with a lightning bolt next to the account's mailboxes in the sidebar. While an account is offline, Mail cannot get or send messages. Anything you write is held in the Outbox until the account is back online.

If the status icon appears and the account will not stay online, Apple also points to VPN or other software that monitors or changes your network connections. It is worth pausing a VPN briefly to see whether the account reconnects.

Fix 1: Take All Accounts Online#

This is the one-click fix for "status offline". Mail does not always reconnect on its own after the connection drops, so you ask it to try again. For most people who see the lightning bolt without a password prompt, this works within a minute.

1. 1

   Look at the sidebar

   A lightning bolt next to an account's mailboxes, or at the end of the Favorites bar, means that account is offline. A warning icon means something needs attention, and clicking it opens Connection Doctor. The exact icon can look different between macOS versions, so go by the behaviour: if Mail is not updating and an icon is there, start here.

2. 2

   Choose Mailbox, then Take All Accounts Online

   In the menu bar, click Mailbox and choose Take All Accounts Online. To reconnect just one account, choose Mailbox, then Online Status, and pick that account, or click the lightning bolt beside it.

3. 3

   Wait a minute and watch for new messages

   Mail fetches whatever arrived while the account was offline. If messages appear and the icon disappears, you are done.

4. 4

   If the icon returns, move to Fix 2

   An offline icon that keeps coming back means the server is refusing the sign-in each time Mail reconnects. That is a credential problem, not a connection that simply dropped.

Fix 2: Re-enter or re-authorize your account credentials#

A rejected sign-in looks like an offline account but does not clear with Take All Accounts Online. Which step you need depends on how the account was added, so work out which of the cases below is yours before changing anything.

1. 1

   Enter the current password at the prompt

   If a password dialog appears, enter the password you use today. If you changed it recently on another device, use the new one. If mail starts arriving, you are done.

2. 2

   Accounts added with Sign in with Google or Microsoft: remove and re-add them

   These accounts sign in with a token the provider issues, not a password stored in Mail, so typing a password into Mail will not fix them. Open System Settings, then Internet Accounts, select the account and remove it, then add it again. The provider's sign-in page issues a fresh token. Labels can differ slightly between macOS versions.

3. 3

   Accounts you set up by hand with IMAP details: update the stored password

   Open Mail, then Settings with Command-Comma, choose Accounts and select the account. Where Mail offers a Server Settings tab for that account, update the password there. That tab is for manually configured accounts, so an account added through a provider sign-in may show fewer options or none.

4. 4

   Two-factor accounts set up by hand may need an app-specific password

   If you entered IMAP details yourself, Apple says iCloud needs an app-specific password for third-party apps and generates it at account.apple.com under Sign-In and Security. Google says app passwords are only for apps that cannot use Sign in with Google, need 2-Step Verification, and are revoked when you change your Google password. Use the provider's own sign-in route when Mail offers one.

If Fix 2 does not hold: rebuild or remove and re-add the account#

Apple's own last step for a Mac that cannot send or receive is to remove the account in Mail and add it back, choosing the correct email provider for the address. That clears a corrupted account setup that no password change repairs. If the mailbox contents look wrong rather than missing, try rebuilding the mailbox first. For Google accounts, the Gmail in Apple Mail guide covers the sign-in specifics.

What is Connection Doctor in Mac Mail and how do you open it?#

Connection Doctor is Mail's built-in connection checker. In Mail, choose Window, then Connection Doctor. It lists your accounts and reports whether Mail can reach each account's servers. If your Mac is online but an account is failing, the problem is in the mail server or the account setup, and the Details column tells you what to do. Double-clicking the text in that column opens the account in Mail's account settings.

Click Show Detail to see log information while Mail tries to connect, and Check Again after you change a setting. Apple's guide does not list a keyboard shortcut for it, so use the Window menu.

Fix 3: Use Connection Doctor to find a silent connection failure#

When Take All Accounts Online does nothing and the password is right, the connection is failing underneath: a wrong server name or port, a security setting mismatch, or a network that blocks the mail ports. Connection Doctor replaces guessing with a per-account result.

1. 1

   Open Window, then Connection Doctor

   Let it finish its check before acting. Note which accounts show a problem and read the Details column.

2. 2

   Click Show Detail for the log

   The log shows what Mail tried while connecting. Read the last lines before the failure to see whether Mail could not reach the server at all or reached it and was refused.

3. 3

   Check the server settings for that account

   For a manually configured account, open Mail, Settings, Accounts, then the account's Server Settings and compare them with the provider's published settings. iCloud Mail uses imap.mail.me.com on port 993 with SSL, and Apple suggests trying TLS if SSL errors. Gmail uses imap.gmail.com on port 993 with SSL. Outlook.com and Microsoft mailboxes use outlook.office365.com on port 993 with SSL/TLS and modern sign-in.

4. 4

   Click Check Again

   Rerun the check after each change so you know which change fixed it. If it still fails, Apple's advice is to contact your email provider to confirm your account details and setup.

Why is Apple Mail so slow on my Mac, when it is not offline?#

Slow is a different problem from offline. If Connection Doctor is clean, accounts show no icon and mail does arrive, but Mail lags, the cause is usually local rather than the connection. A mailbox that has drifted out of step with the server is the common one, and rebuilding the mailbox forces Mail to redownload and reindex it. If the slowness shows up mainly when you search, see Apple Mail search not working.

Mail also slows down in step with how much it has to keep in sync. Many accounts, very large mailboxes and heavy attachments all add work. If you rely on several accounts at once, a quick test is to temporarily turn off the ones you do not need and see whether Mail speeds up. That points to the account to fix first rather than to a general fault.

How to avoid it coming back#

Most sync failures follow a change you can predict.

• Update the stored password in Mail as soon as you change it anywhere else, so Mail does not keep retrying a rejected sign-in.
• Act on provider security emails promptly. When Google, Apple or Microsoft asks you to re-verify, a link in that message usually fixes the account before it goes offline.
• Prefer Sign in with Google or Microsoft when adding an account in System Settings, then Internet Accounts. Those tokens refresh on their own, while a hand-entered app password stops working the moment the account password changes.
• Keep macOS up to date, since Apple fixes Mail bugs in point updates.

If you do this on every device#

Client-side IMAP means each device holds its own connection, so a changed password or revoked token needs the same repair everywhere. We build AI Emaily, an AI-native email client that syncs on the server, so reconnecting a mailbox once covers its web, desktop and iOS apps. That does not fix Apple Mail itself, which keeps its own connection. If you want to compare, there is a 7-day free trial on Pro or Autopilot.