Email problems can come from several different places — DNS, mail server settings, your local email client, mailbox status, or spam filtering. This guide walks through the most common causes in the order they're usually worth checking.

First: Identify the Type of Problem

Before troubleshooting, work out exactly what's failing:

• Can't send, but can receive → usually an outgoing (SMTP) configuration or authentication issue.
• Can't receive, but can send → usually an incoming (IMAP/POP) setting or storage quota issue.
• Can't send or receive at all → often DNS, domain status, or account-level issue (suspended mailbox, expired domain, etc.).
• Emails bounce back → check the bounce message; it usually names the specific reason (see below).

Common Causes

Domain or DNS Issues

• Domain expired or suspended: If your domain has expired or is in a grace/redemption period, DNS may stop resolving, breaking email entirely.
• Recent DNS changes not yet propagated: DNS changes can take time to propagate — this is often mistaken for a broken configuration.

Incorrect Mail Client Settings

Double-check the settings in your email client (Outlook, Apple Mail, Thunderbird, mobile mail app, etc.):

• Incoming server (IMAP/POP) — correct hostname, port, and encryption (SSL/TLS).
• Outgoing server (SMTP) — correct hostname, port, encryption, and that authentication is enabled (most providers now require SMTP auth to prevent abuse).
• Username/password — especially after a recent password change.

Mailbox Storage Quota Exceeded

If a mailbox is full:

• Incoming mail will typically bounce back to the sender.
• Outgoing mail may still work in some configurations, but not always.

Account Suspended or Disabled

Mailboxes can stop working if:

• The hosting account or domain is suspended (e.g. unpaid invoice, policy violation, expired domain).
• The specific email account was disabled or deleted by an administrator.

Troubleshooting Checklist

1. Confirm the issue is domain-wide or account-specific (test with a second mailbox on the same domain, if you have one).
2. Confirm the domain isn't expired or suspended.
3. Verify mail client settings (server, port, encryption, authentication).
4. Check mailbox storage usage.
5. Check bounce-back messages for a specific error/reason code.
6. Check if the sending IP is blocklisted.