Problems sending or receiving emails

If there is a problem with sending or receiving emails, you need to find the cause as precisely as possible, because there are many possibilities.

First you need to be clear about what exactly

is not working:

1. Sending emails from an email program on your PC through our SMTP server (via the SMTP protocol)
2. Receiving emails in an email program on your PC from our mail server (POP3 or IMAP protocol)
3. A problem with the webmail interface - you cannot log in or cannot receive/send
4. Sending emails from web hosting in PHP
5. Sending emails from a virtual or dedicated server
6. Delivering emails to a virtual or dedicated server
7. A lost email - sending/receiving seems fine, but some email does not reach its destination

The individual situations are covered in the chapters below.

1. Sending emails from an email program through our SMTP server

If the email can be sent from the program but does not arrive at its destination, follow the instructions in 7. A lost email below in this article.

Check that your email program (Outlook, Thunderbird, etc.) is set up exactly according to the guide for setting up sending email.

2. Receiving emails in an email program on your PC from our mail server

If the email program communicates with our mail server without problems, but emails are not arriving or a particular email did not arrive, follow the instructions in 7. A lost email below in this article.

Check that your email program (Outlook, Thunderbird, etc.) is set up exactly according to the guide for setting up email (Outlook, Thunderbird).

3. A problem with the webmail interface

If the webmail interface works fine but emails are not arriving, a particular email did not arrive, or a sent email did not reach its destination, follow the instructions in 7. A lost email below in this article.

If you cannot log in to the mailbox via webmail:

• make sure you are entering the login name correctly (the mailbox name including the domain, e.g. karel@example.com)
• make sure you are entering the password correctly

4. Sending emails from web hosting in PHP

From PHP scripts on our web hosting, emails can be sent only by calling the mail() function. A script cannot connect directly via the SMTP protocol on port 25.

If emails sent from PHP do not reach their destination, follow the instructions in 7. A lost email below in this article.

5. Sending emails from a virtual or dedicated server

If there is a problem with sending emails on a virtual or dedicated server:

• check the relevant mail log (especially /var/log/maillog), you will often find the problem there
• make sure the reverse records for your server's IP address are set up correctly

6. Delivering emails to a virtual or dedicated server

If there is a problem with receiving emails on a virtual or dedicated server:

• check that the MX records of the domain are set up correctly
• check the relevant mail log (especially /var/log/maillog)
• make sure the email was not discarded or moved by an anti-spam tool on the server

If you do not know how these records work, contact your hosting provider.

7. A lost email

This chapter describes what to do when an email was sent successfully (the SMTP server accepted it, the email was sent correctly from a PHP script, or someone sent you an email from somewhere) but did not reach its destination.

Check the following possibilities one by one:

• The email may have bounced back to the sender as undeliverable - proceed according to the error message in the non-delivery email.
• The email may have ended up in the spam folder, make sure it is not there. Please note that the spam folder is not visible on our mail server via the POP3 protocol, you can only reach it via the IMAP protocol or the webmail interface. More in the article Unsolicited email (spam).
• The target mailbox may be full, and in this case the sender should also receive a notice that delivery was not possible.
• The recipient's domain may have incorrect MX records or none at all. Fix this by setting the correct MX records in the domain's DNS.

If you have not found the cause of the lost email and it has not arrived even after some time (several hours), contact customer support via the contact form and provide the following information:

• where the emails are sent from (through our SMTP server, from PHP on web hosting, from elsewhere)
• the most precise date and time the message was sent
• the sender's email address
• the recipient's email address
• the full text of any error message (or attach a screenshot)

Common error messages

• Relay access denied - the destination mail server does not recognize the recipient's email address. Either the MX records of the domain are set up incorrectly (mail is delivered to the wrong mail server) or the mailbox does not exist on the server.
• Intrusion Prevention active - you are probably sending emails from an IP address that is listed on one of the blacklists. This is usually because you send emails directly from a home computer rather than through an SMTP server of your internet provider or web hosting. Or the IP address really is blocked because of spam being sent.