Why You Can’t Send Mail When Connected Through Another ISP

• If you have an email address from another provider (like @telkomsa.net) and you’re using an Mweb internet connection, you might find that you can’t send emails. This isn’t a fault with your Mweb connection - it’s a restriction based on how email delivery works across the internet.

  Why This Happens

  When you send an email, it must go through the SMTP server that belongs to the same provider as your email address. This rule follows international RFC-compliant email standards (RFC 5321 and RFC 6409) designed to prevent spam and ensure mail is sent securely.

  For example:

  • If your address is @mweb.co.za, you should use smtp.mweb.co.za.

  • If your address is @telkomsa.net, you should use e.g. smtp.telkomsa.net.

  If you try to send through a different provider’s SMTP server (for instance, using Mweb’s SMTP server for a Telkom address), the mail will be rejected or fail to send.

  Important Note

  This isn’t an Mweb network or connection problem. Your emails will send successfully once your outgoing mail server is updated to your email provider’s correct SMTP details.