Emails – Blocked Messages

  E-Mails

This article addresses issues with email being blocked by mail servers. If the blocking occurs in a mail client with the exception of WebMail, troubleshoot it using the manual or support of the client in question.

Other problems with the operation of e-mails are solved in the article Emails – Troubleshooting.

In this article, you will learn:

Email Blocking

Email blocking normally means a situation where a mail server refuses to send or receive an email for some reason. Another common problem can be caused by invalid DNS records, which can appear to block emails when received.

Emails may be blocked during:

  • Sending the email, such as blocking SMTP or disabling the PHP mail() function. You work to resolve this problem with your email or web hosting service provider.
  • Receiving the email, by fault of a routing error, or message rejection. This problem may be on either the sender’s, or receiver’s side.

Sending Block

If you are blocked from sending mail on your Mailhosting, Webhosting, WMS or WebSite, the system will not allow you to send any messages. Mail clients usually returns an error message, scripts fail.

Common reasons for being blocked from sending emails include:

Daily Quota

The system resets the daily email quota automatically every day at midnight (CET). We do not perform manual resets on request.

You can send emails from hosting services in two ways – using the SMTP mail protocol or the PHP mail() function. Each method has its own quota for sending emails (usually 500 e-mails per day, 50 for web hosting with the LowCost plan).

If you exceed the quota, the system will block sending mail that way until midnight, when it resets the quota.

WEDOS WebMail error message: mailbox over quota
WebMail error message: mailbox over quota

Preventive Blocking

If we detect problematic behavior in a mailbox or the entire service, we block it to prevent further damage and a negative spam evaluation of our mail servers. As withc the daily quota, we distinguish between sending mail via SMTP and the PHP mail() function.

Common reasons for us to block mail include:

WEDOS WebMail error message: mailbox disabled
WebMail error message: mailbox disabled

If we block your mail, a technician will notify service’s billing email with instructions on how to solve the problem. Take the recommended actions and then request the block to be removed in response to the technician’s message.

Full Mailbox

If the mailbox is full, you can still send emails, but they will not be saved in the Sent or Drafts folders.

You can solve the situation by increasing the mailbox capacity according to the instructions Email – Mailbox Storage Upgrade, or by deleting emails according to the instructions WebMail – Deleting Emails.

Other Sending Blocks

If you suspect that the server is not sending emails, even though the service is not limited, ask support to investigate via the form. Specify:

  • How are the emails sent (SMTP via mail client or script, PHP mail);
  • Date and time of sending the test message;
  • Sender email address;
  • Recipient email address;
  • Full text or screenshot of any error message.

Receiving Block

If an email is blocked by the recipient’s server, the sender usually receives a message describing why the message was rejected. According to this message (or if you don’t receive it at all), you can most easily distinguish whether the delivery failed due to a rejection by the server or another error.

Common reasons for email blocking include:

SPF or DKIM Issue

Problems with SPF and DKIM can either lead to messages being spammed (in which case the recipient’s server sometimes does not send a undeliverable message), or rejecting them and notifying the sender.

SPF is a DNS TXT record containing a list of servers that are authorized to send e-mails from addresses on this domain. You can find more information and instructions on setting SPF records in the article Email – SPF Record, or from your mail hosting provider.

The error message for incorrect SPF settings varies depending on the recipient, WEDOS sends the following error:

550 5.7.1 <address@recipient.tld>: Recipient address rejected: Please see http://www.openspf.net/Why?s=... (in reply to RCPT TO command)

To set up DKIM correctly, verify that you have the following records in DNS:

Název                       Typ     Data
key1.wedos-dkim._domainkey  CNAME   key1.dkim-we.wedos.net
key2.wedos-dkim._domainkey  CNAME   key2.dkim-we.wedos.net

For domains directed to Webhosting, WMS, or WebSite, the system generates these records automatically.

Blacklisting

A server can reject messages based on a blacklist, where it finds either the email address (a specific mailbox or the entire domain) or the IP address of the mail server.

There are a large number of blacklists. One of them can be configured directly by the user, for example according to the article Emails – Blacklist/Whitelist in Customer Admin Panel. The server on which your address is blacklisted in this way, replies with a message after a certain time:

550 5.7.1 <address@recipient.tld>: Recipient address rejected: sender blacklisted

Other blacklists are public or internal, and you ask the operator of the sender’s mail servers to remove the address from the blacklist. Therefore, if you are sending an email from our Webhosting, WMS, or WebSite, and you receive an email notification mentioning the location of the blocked mail server’s IP address on the blacklist, send us the wording of the error message via the form. The next procedure is handled by the technician.

Unavailable Mailbox

If the inbox is full, it cannot receive any more emails.

You can solve the situation by increasing the mailbox capacity according to the instructions Email – Mailbox Storage Upgrade, or by deleting emails according to the instructions WebMail – Deleting Emails.

To troubleshoot an otherwise unavailable mailbox, such as problematic DNS records, see the article Emails – Troubleshooting.

PHP mail() and return-path

If your emails sent via the PHP mail() function are not delivered, check that it contains a correct return-path parameter according to the pattern:

mail('address@recipient.tld','Subject','Text','','-f address@sender.tld');

Avoid setting the return-path to the address entered by the user in the form and instead use the address on the domain you’re sending the email from.

Other Receiving Blocks

If you suspect that the server is rejecting emails, even though the service is not limited, ask support to investigate via the form. Specify:

  • How are the emails sent (SMTP via mail client or script, PHP mail);
  • Date and time of sending the test message;
  • Sender email address;
  • Recipient email address;
  • Full text or screenshot of any error message.

FAQ

Question: Potřebuji denně odesílat víc než 500 e-mailů, jak to mám zařídit?
Answer: If you need to send out newsletters and other bulk correspondence, even solicited, which our terms disallow, use a service specifically designed for sending bulk emails. If 500 emails a day are not enough for you for normal correspondence, contact us via the form. Include the name of the hosting service, the desired new daily limit and what you need the extra emails for.

Question: What is the daily limit even for? Can you reset it?
Answer: The daily limit is used to limit the total mail sent by our servers, because the amount of emails sent from a server affects the behavior of spam filters towards it. The limit resets every day at midnight (CET), customer support does not intervene in this process.

Question: Why do emails go to WebMail but not to the mail client?
Answer: The mail client may be incorrectly configured to receive mail, send mail, or both. Common errors will be eliminated by properly configuring servers, ports, and security according to this guide. If problems persist, resolve the error with the email client support.

Děkujeme za zpětnou vazbu!