Gmail Will Not Send From Apple Mail

Quick answer

Send the same message from Gmail in a browser first. If that works, the account is fine and the fault is local. Then check whether Mail has been set offline, look at the outgoing server list for an entry marked offline, and establish whether the account needs an app password. Those three cover the large majority of cases.

Separate the account from the app

Do this before changing any setting, because it saves time in both directions.

1. Step 1

   Open Gmail in a browser on any device and send a short message to yourself.

2. Step 2

   Note whether it arrives.

3. Step 3

   If it arrives, the account, the password, and Google's sending servers are all working. Work on the Mail app.

4. Step 4

   If it does not arrive, the problem is with the account itself and nothing in Mail will fix it.

Keep that result to hand. It is the first thing anyone helping you will want to know.

Is Mail offline?

Apple Mail can be placed offline deliberately, and it queues everything silently when it is. There is a small indicator beside the mailbox list when this is the case, and the Mailbox menu on a Mac offers the option to bring all accounts back online.

This catches people who lost connectivity on a train or a plane weeks earlier. Mail went offline, the connection came back, and Mail did not. Check this first on a Mac; it costs one glance.

The outgoing server list is where sending breaks

Mail keeps a separate list of outgoing servers, and that list is where most sending faults live. Two problems recur.

The first is duplicate entries. Adding an account more than once, or migrating a Mac from an older one, leaves several similar-looking server entries. Mail may be trying one that is misconfigured or marked offline while a correct entry sits beside it.

The second is the option that allows Mail to fall back to a different server. When that option is left enabled, Mail may attempt to send a Gmail message through an unrelated provider's server, which refuses it because the address does not belong there. Restricting the account to its own server makes failures explicit instead of confusing.

Open the outgoing server list, remove entries that belong to accounts you no longer have, and check that the one in use is not flagged as offline.

Authentication is the most common single cause

How the account was added to Mail determines what credential it needs, and this is where most people get stuck.

An account added using the built-in Google option signs in through Google's own window and is generally maintained automatically. It can still fall out of authorization after a password change, and the fix is to re-authorize the account in the system's internet accounts settings rather than to retype a password in Mail.

An account added manually as an IMAP account uses a stored password. If two-step verification is switched on, an ordinary account password will often be refused for mail programs, and a separate app password generated for this purpose is required instead. A password that works on the website and fails in Mail is the signature of exactly this situation.

One further trap on a Mac: the keychain can hold an old password that Mail keeps presenting. If prompts repeat even after you enter the current credential, the stored copy is likely to be the culprit.

Send-as addresses need verification

If you send from an address that is not the account's own, such as a personal domain or an older address routed through Gmail, that address has to be verified in the Gmail settings before Google will send on its behalf.

An unverified alias fails at the sending stage even though everything else is correct. Check which address Mail has selected in the From field of the stalled message, and confirm that same address appears as verified in the account's settings. Changing the From field to the main account address is a quick diagnostic.

Attachments and message size

Google applies a limit to total message size, and encoding inflates attachments as they are prepared for transmission. A file that looks acceptable on disk can exceed the ceiling once encoded, and several moderate files together do so easily.

Test by sending a short message with no attachment at all. If that goes immediately, size is your answer. Mail offers a service that sends large files as a download link instead, and compressing a folder or reducing image dimensions works just as well.

Messages that sit in the outbox without complaint

An outbox message with no error is a distinct situation and has its own causes.

Opening a queued message to change a word takes it out of the send queue, and it then waits indefinitely with no warning. The fix is to open it and send it again deliberately. A very large message can also appear stalled while it is still uploading, so check whether progress is being made before intervening.

If a single message refuses to move while everything else sends, treat that message as the problem rather than the account. Copy its text into a fresh message, attach the files again, and send that instead.

Rejections that are not your fault

Some failures originate at the other end. A recipient's server may refuse mail for a full mailbox, an address that no longer exists, or a policy of its own. These produce a returned message rather than an outbox error, and the returned message contains the reason.

Read the wording of a returned message carefully before changing anything on your side. There is nothing to fix locally when the answer is that the recipient's mailbox is full.

Sending limits

Gmail restricts how much mail an account may send in a day, and the limits are lower for free accounts than for paid ones. Someone who has just sent a newsletter to a large personal list can find sending blocked for the rest of the day, with the block clearing on its own.

If sending stopped abruptly after a large mailing, wait rather than reconfiguring. Also note that mail programs retrying a stuck message repeatedly can contribute to reaching a limit.

Details worth recording

Note whether webmail sends successfully, the exact error wording from Mail, the operating system and Mail version, how the account was added, whether two-step verification is on, whether an app password was generated, which address is in the From field, whether any message sends or none do, the size of any attachment, and what changed recently. Never include the password itself.

When to ask for help

Independent help is useful before you remove and re-add an account, which on some setups risks local mail that is not stored on the server, and when you need to work out whether the account should be added through the Google option or manually. Anything involving a work or school account may also be governed by administrator policy that overrides local settings.

Important disclaimer

This page is general independent information and is not official support for Apple or Google. Menu locations, account setup options, sending limits, and app password requirements change over time and differ between macOS and iOS versions. Back up important mail before removing an account from any device.