Overview
Some Internet Service Providers (ISPs) block SMTP Port 25 to reduce spam and prevent malware from sending unsolicited emails. If your ISP blocks this port, your email application may be unable to send outgoing emails, even though receiving email still works normally.
This is a common issue and does not indicate a problem with your hosting or email account.
What Is Port 25?
Port 25 is a traditional network port used for sending email (SMTP).
Many ISPs restrict this port to protect their network and customers from spam abuse.
Common Symptoms
You may experience one or more of the following:
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Unable to send emails
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Emails remain stuck in the Outbox
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Error messages such as “Connection timed out” or “SMTP connection failed”
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Receiving emails works, but sending does not
How to Fix This Issue (Recommended Solutions)
Option 1: Use an Alternative SMTP Port (Recommended)
Most email services support alternative ports that are not blocked by ISPs.
Update your email client’s outgoing mail (SMTP) settings as follows:
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SMTP Server: mail.yourdomain.com
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Port: 587 (recommended) or 465
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Encryption: TLS (Port 587) or SSL (Port 465)
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Authentication: Enabled
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Username: Your full email address
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Password: Your email password
These ports are widely supported and work on most networks.
Option 2: Use Webmail
If you cannot change your email settings, you may access your email using webmail:
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Log in via
https://yourdomain.com/webmail -
Webmail is not affected by ISP port restrictions
Option 3: Use Your ISP’s SMTP Server (Advanced Users)
Some ISPs allow email sending only through their own SMTP servers.
If required, contact your ISP for their SMTP details.
Why Do ISPs Block Port 25?
ISPs commonly block Port 25 to:
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Prevent spam and email abuse
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Reduce the spread of malware
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Protect their network reputation
This practice is standard worldwide and affects many residential and mobile internet connections.
Important Note
Our mail servers support Port 25, but if your local ISP blocks it, the connection will fail before reaching our server.
