Interactive fix flowchart

Email not sending

Fix emails stuck in outbox, Gmail not sending, Outlook not sending, SMTP errors, attachment problems, email rejected, and messages that bounce back.

All fixes in this guide

Fix: Email stuck in outbox

An email stuck in the outbox usually means the mail app cannot connect to the sending server, the attachment is too large, the app is offline, or the account needs you to sign in again.

Fix: Gmail not sending in browser

Gmail in a browser can fail to send because of internet problems, a large attachment, browser extensions, cached data, account storage issues, or a temporary Gmail problem.

Fix: Gmail app not sending

The Gmail app may not send because of a bad connection, sync problem, stuck outbox, large attachment, account sign-in issue, or app cache problem.

Fix: Outlook not sending emails

Outlook usually fails to send when it is offline, a message is stuck in the outbox, the attachment is too large, the account password changed, or SMTP/account settings are wrong.

Fix: Outlook.com not sending in browser

Outlook.com can fail to send because of browser issues, attachments, account limits, storage problems, extensions, or a temporary Microsoft service problem.

Fix: Outlook app not sending on phone

The Outlook mobile app may not send because of connection problems, a stuck outbox, large attachment, account sign-in issue, sync problem, or app bug.

Fix: Email won’t send with attachment

Emails with attachments fail when the file is too large, blocked by security rules, still uploading, stored only in the cloud, or using a file type the mail service refuses.

Fix: Email says address not found

Address not found usually means the recipient address is mistyped, no longer exists, has an old domain, or the recipient's mail server rejected it.

Fix: Email says recipient mailbox is full

Mailbox full means the recipient's email account has no space left or cannot accept new messages right now.

Fix: Email bounced back

A bounced email means the receiving mail server rejected the message or could not deliver it.

Fix: Email rejected because of SPF, DKIM, or DMARC

SPF, DKIM, and DMARC errors mean the receiving server could not verify that your email was allowed to send from your domain.

Fix: Can receive email but cannot send

If you can receive email but cannot send, the receiving settings are working but the outgoing SMTP server, authentication, password, port, or provider settings may be wrong.

Fix: Website or domain email not sending

Domain email fails when DNS records, SMTP settings, website mail settings, SPF, DKIM, DMARC, or hosting mail limits are wrong.

FAQ

Why is my email not sending?

The most common causes are internet connection problems, a message stuck in the outbox, a large attachment, wrong recipient address, account sign-in problem, SMTP settings, or the mail server rejecting the message.

What should I check first if email will not send?

Check your internet connection, confirm the recipient address, remove large attachments, restart the mail app, and see whether the email is stuck in the outbox.

Why is my email stuck in the outbox?

Email gets stuck in the outbox when the mail app cannot connect to the sending server, the attachment is too large, the account needs sign-in again, or the app is offline.

What does SMTP mean?

SMTP is the system used to send email. If SMTP settings, authentication, or the sending server are wrong, email may receive normally but fail to send.