Mail not delivered from or to the server

First, find out which direction fails#

• Outgoing: a customer sends to an outside address and it never arrives, bounces, or lands in spam.
• Incoming: mail sent to a mailbox on the server never shows up.
• Panel mail: password resets and notifications from the panel do not arrive.

Each has different causes. If Tools & Settings › Mail Server Settings says the mail server is not installed, install MailEnable Standard under Tools & Settings › Server Components first.

Outgoing mail stays in the queue#

Check 1: Is port 25 blocked?#

Many cloud and VPS providers block outgoing port 25. Go to Tools & Settings › Smarthost and click Check now on the Check mail delivery card. It tests whether the server can reach other mail servers on port 25, logs in to a saved smarthost and shows the outgoing queue.

Fix: ask the provider to unblock port 25, or relay through a smarthost: tick Relay all outgoing mail through this server, enter Server and port (587 is the default; use 587 rather than 465), User name and Password, and click Save.

Check 2: Is the sender over its limit?#

Tools & Settings › Outgoing Mail Control shows the recipients per hour for each domain and subscription, and the messages refused in the last 24 hours. Rows marked At limit explain refusals. Raise the limit for the domain, the plan or the server default in Mail Server Settings if the volume is legitimate; if it is not, the mailbox may be compromised, so change its password first.

Check 3: Is the mail service on?#

On the subscription's Mail page, Mail Settings tab, check that Mail service is on for the domain and that the plan includes mail.

Outgoing mail arrives as spam or bounces#

Look at the bounce message or ask the recipient for the headers. Then check:

• Reverse DNS. The server's IP address should have a PTR record matching the Mail host name in Mail Server Settings. Only your hosting provider can set it.
• SPF and DKIM. The domain's card on the Mail Settings tab shows its SPF, DKIM and DMARC records. Turn on DKIM and make sure the records are in public DNS; see set up DKIM, SPF and DMARC.
• Block lists. If the server's IP is listed on a public block list, find out why (often a hacked mailbox or website script) and request delisting after fixing it.

Incoming mail does not arrive#

Check 1: MX records#

The domain's MX record must point at mail.<domain> (or another name) that resolves to this server. If the server hosts DNS, the template creates both. If DNS is elsewhere, compare the records there. Mail to a domain whose MX points at another provider never reaches this server.

Check 2: Ports#

Inbound TCP 25 must be open in Windows Firewall and any provider firewall. Under Tools & Settings › Firewall, the Mail: SMTP service must not be set to Nobody or limited to certain addresses, and Panic mode must be off.

Check 3: Spam filter and antivirus#

Tools & Settings › Spam Filter may delete spam instead of tagging it (Spam is deleted), or a sender may be on the Block list. Greylisting delays mail from unknown servers once, so a first message can take a while. var\logs\mail-pickup.log in the StackRegent folder records spam decisions and which check scored the message. Infected messages are quarantined by Tools & Settings › Antivirus; Threats found in mail lists them.

Check 4: Mailbox quota and unknown users#

A full mailbox refuses new mail. Check the mailbox size against the plan's Mailbox size. If the address does not exist, the domain's Mail to unknown users setting decides whether the message is rejected, forwarded or redirected.

Panel notifications do not arrive#

Go to Tools & Settings › External SMTP Server, check Send through and the sender address, and use Send a test message. If the panel sends through this server's own mail server, the outgoing checks above apply. Monitoring alerts use the same path.

The mail server chapter describes every mail setting; customers find mailbox setup in the email guide.