Why can’t I send email?

Emails may fail to send for a variety of reasons. Here are some of the most common causes:

Why can't I send email?

Network connectivity issues

If you have a weak internet connection or are disconnected from the network, emails will not be able to send. Check your network connections and try sending the email again once connectivity is restored.

Full mailbox

If the recipient’s mailbox is full, incoming emails may get rejected. The recipients should clear space in their inboxes or contact their email provider for assistance.

Improperly configured email clients

Incorrect SMTP or POP/IMAP settings in an email client can disrupt sending and receiving emails. Ensure these settings match those provided by your email host.

Problems with email provider

Issues with your own or the recipient’s email service, like Gmail, Outlook or Yahoo, could block emails. This is usually temporary.

Email server downtime

If the email server for either party is down for maintenance or due to a technical glitch, emails exchange will halt. Servers may take some time to come back online.

Spam filters

Overactive spam filters may sometimes block legitimate emails accidentally. Whitelisting important contacts may help avoid this issue.

Troubleshooting email delivery issues

If your emails won’t send, try these troubleshooting techniques and tips:

Check error messages

Carefully read any bounced email notifications or error messages shown by your email client. These explain exactly why that particular email failed to send.

Verify network connections

Make sure you have an active internet connection. For mobile devices, switch between WiFi and mobile data to check if one network is facing downtime.

Test with alternative clients

Try sending emails from alternative platforms like a web browser, mobile app or desktop client to check if issues lie with a particular email client.

Contact email provider

If the problem persists across email clients, contact your email hosting provider regarding server or account specific issues that could cause failed email delivery.

Check if recipients received the email

Before resending any emails that seemingly failed the first time, check if recipients already got them. Some error messages are inaccurate.

Clear space in recipients’ inbox

If recipient mailboxes are completely full, ask them to delete older emails and free up space for new messages that are failing to be delivered.

Key things to check in different email clients and services

The exact troubleshooting steps will vary based on which email service and client you use. Here is an overview:


  • Check Google server status page for downtime
  • Ensure internet connectivity
  • On Android, check battery optimization exceptions for Gmail app
  • Disable browser extensions when using Gmail web interface


  • Verify Microsoft Exchange server health
  • Make sure offline settings are disabled
  • Disable malware protection temporarily to check for conflicts

Apple Mail:

  • Check Apple Systems Status page
  • examine Accounts preferences for issues
  • Restart devices and test email connectivity

Yahoo Mail:

  • Check Yahoo Mail server status page
  • Check account security settings for blocked senders
  • Clear space in your Yahoo mailbox storage

Mobile device email apps:

  • Restart your phone
  • Check for app updates and install them
  • Toggle between Wifi and mobile data

Third-party email clients:

  • Carefully inspect all SMTP, IMAP and POP settings
  • Disable any proxy connections temporarily
  • Check for errors related to security certificates

Webmail interfaces:

  • Try using a different browser
  • Empty browser cache and cookies
  • Temporarily disable browser extensions

Takeaway points

  • Email delivery can fail due to various technical issues with clients, providers, servers, devices or networks. Carefully read error messages for clues.
  • Thoroughly troubleshoot by testing email sending through alternate platforms on your domain.
  • Check server status pages of email providers for downtime notifications before further diagnosis.
  • Contact your email host if issues seem account or server-specific for quickest resolution.
  • On mobile devices, toggle between WiFi and cellular connectivity to identify network issues quickly.


Emailing issues can certainly be frustrating but are often caused by temporary glitches that clear up on their own. When emails repeatedly fail to send for you, methodically go through the various troubleshooting steps outlined above to identify and resolve the specific point of failure. If problems continue despite your best efforts, don’t hesitate to reach out for assistance from your email provider’s tech support team.

Frequently Asked Questions (FAQ)

  1. Why are my outgoing emails getting stuck in the outbox?
    If your sent emails remain stuck in the outbox, it generally indicates connectivity issues with the SMTP server. Check your internet connection and restart your device. Also double check SMTP settings or contact email admin.

  2. Why is Gmail not sending emails with attachment?
    Large attachments in Gmail may sometimes get blocked. Try compressing files to reduce size below 25MB limit or switch from Gmail app to browser for sending large attachments.

  3. How do I troubleshoot error message 550 or 540 when trying to send emails?
    550 and 540 errors during email sending signify invalid or unauthorized user credentials accessing SMTP server. Update password if recently changed or contact admin.

  4. Why am I getting error 554 while sending emails?
    554 errors mean the SMTP server has rejected your from address as invalid or unverifiable. Make sure the From field matches the email tied to your account login credentials.

  5. No response from recipients – are my sent emails not being delivered?
    If recipients don’t respond, first check your Sent folder for send confirmations. Also verify recipients received using Read Receipts or view email headers to diagnose failed deliveries.

  6. How do I check if my outgoing emails are being blocked?
    Signs of blocked outgoing emails include delivery failures to all recipients with no specific error messages. Contact your email admin or provider to check security settings on your account blocking sends.

  7. Sent email got disappeared – Where did it go?
    If a successfully sent email later disappears from Sent folder, check your email account’s sync settings across devices. Change settings to leave copies of sent mail on server instead of just locally.

  8. How to troubleshoot error 552 related to email storage limits?
    552 errors indicate recipient inbox is completely full which blocks incoming messages. Clear old emails from their account or have them upgrade storage capacity to resolve.

  9. Gmail says “message rejected by server” – what do I do?
    This error typically appears when sending to invalid or improperly formatted email addresses. Double check the spelling of recipients’ email addresses before trying to resend any bounced messages.

  10. Why does my computer say connected to the Internet but unable to send emails?
    If online activity works but emails fail, connectivity issue may be specific to SMTP port. Contact your ISP or network admin to troubleshoot port 25 blockages required for email sending.

  11. How do I fix error 451 when trying to send mail?
    451 errors during email delivery relate to security issues like invalid TLS certificates or protocol mismatches. Check security settings between client and SMTP server configurations.

  12. Why does my iPhone say it’s connected but I can’t send emails?
    On iPhones, open Settings > Passwords & Accounts and disable Account Syncing temporarily under each logged-in account. Then toggle it on to reconnect.

  13. Can I retrieve an email stuck in Outbox if my computer dies?
    If a computer crashes before sending an email in its Outbox, try restarting while holding Shift key during bootup to access Safe Mode then immediately retrieve stuck emails. Else try reconnecting the hard drive to another device to recover email files in Outlook data folders before they are overwritten with queued send requests.

  14. Why are my personal emails going to recipients’ spam folder?
    Legitimate personal emails may sometimes incorrectly get spam filtered if sending from a new email address lacking send reputation. Ask recipients to mark your messages as ‘Not Spam’ to build deliverability going forward.

Leave a Comment