Certificate domain mismatch error when connecting to a DreamHost mail server

You may receive a "domain mismatch" warning or an error when connecting to a DreamHost mail server if you use your DreamHost mail server subdomain. For example:


The following information shows you how to resolve this situation.

In the past, it was possible to use mail.example.com to connect (where example.com is your actual domain name). Due to how modern mail clients handle security, this is now NOT recommended as it may cause connection errors. Please ensure you are only using your email cluster servername (shown below) when connecting.

Connecting directly to your DreamHost mail server

Instead of using mail.example.com, you can use the name of your specific DreamHost mail server instead.

To determine which server name to use:

  1. Log into your DreamHost Panel.
  2. Navigate to the (Panel > 'Support' > 'Data Centers') page.

    Under the 'Mail service' section, your mail server appears to the right of any domain. In the following example, it’s homiemail-sub4:

  3. Use the matching server name in the following table for the incoming AND outgoing server in your mail program.
    Email Cluster Server Name
    homiemail-sub3 sub3.mail.dreamhost.com
    homiemail-sub4 sub4.mail.dreamhost.com
    homiemail-sub5 sub5.mail.dreamhost.com
    homiemail-master homie.mail.dreamhost.com

    This example shows homiemail-sub4, so enter 'sub4.mail.dreamhost.com' into your mail client to connect.

Recent updates to DreamHost's mail certificates

On January 19, 2017, DreamHost updated the SSL certificates on all mail servers. Because the SSL certificate was updated, a message appears when you open your mail client and prompts you to accept the new certificate. This certificate is completely safe for you to accept. Once your mail client saves the new certificate, your email client functions normally again.

Mac Mail users: There have been a few reported issues with Mac Mail not saving the new certificate at first. Try several times to accept the certificate with the 'Continue' button. Some users report that after a few tries, the certificate is saved. If it still cannot connect after these attempts, use your mail cluster for the Mail Server name on your account. For example, sub5.mail.dreamhost.com. You can see which mail cluster your account users in the panel on the (Panel > 'Support > Data Centers') page.

iPhone (iOS) users: First, try going to 'Settings > Mail > Accounts'. Click the account and address, and then re-enter the hostname. If this doesn't work, try setting up email as a new account. Go to 'Settings > Mail > Accounts > Add Account'. When the message "Cannot Verify Server Identity" appears, click "Details" below that message. Be sure to click the Trust button in the top-right corner:


If needed, repeat this process 2–3 times to take effect permanently. You should also use your mail cluster for the server/host name with this setup.

See also

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