Cannot send emails: How to fix email sending issues

Sometimes it happens: you simply cannot send emails. You open your favorite mail client or software (Mozilla Thunderbird, Outlook Express, SendBlaster...), write a few lines, insert the recipients' addresses, click "Send" and... An error is returned. Why?

If you can't send your emails, the problem is very likely (but not exclusively) related to your SMTP server – the server taking care of the whole email delivery process. That is why it's always better to rely on a professional server, even if you don't have big mailing needs: for instance turboSMTP offers a handy free plan of 6.000 emails/month, lifetime.

And here's a checklist to understand why you're unable to send emails and troubleshoot any major problem:

  1. Check your internet connection. Yup. It happens. So first of all, be sure that you're connected to the internet!
  2. Check your SMTP server details. This is an extremely common mistake: you have set up your mail client with the wrong SMTP parameters. To find out yours, please refer to our list of the most common ones or ask directly your provider.
  3. Verify all usernames and passwords. Another small mistake that happens usually, so doublecheck your login details.
  4. Check your SMTP server connection. Now this is trickier: even if your SMTP details are correct, the server itself can be down or not functioning for some reason. Here's a list of all the SMTP error codes to get your bearings; and remember again that using a professional outgoing server this won't happen again.
  5. Change your SMTP port. The outgoing mail server uses normally port 25, but some ISPs may block it due to the increasing spam traffic that's been passing through it. You can use then port 587 or 465; for more information read our article about SMTP ports.
  6. Control your antivirus or firewall settings. Sometimes an outgoing mail server can conflict with the computer's protection systems. So verify that your firewall or antivirus are not blocking it, setting up a proper exception rule.
24-7 phone support +1(646) 963-6059