Fixing Apple Mail “Cannot Verify Server Identity” After RISP Mail Server Updates

Overview

After RISP updates or renews the security certificate on our mail servers, Apple Mail may display warnings such as:

• “Cannot verify server identity”
• “Mail can’t verify the identity of the server”
• “This certificate is invalid”

This does not mean your email account is compromised.
Apple Mail often remembers the old certificate and needs to be updated to trust the new one.

The steps below will help you quickly resolve the issue.

Step 1 — Quit Apple Mail Completely

1. Click Mail in the top-left corner of your screen.
2. Select Quit Mail.
3. Make sure the app is fully closed (the dot under the Mail icon should disappear).

Step 2 — Remove Old Certificate Information

1. Open Keychain Access
   • Press Command + Space, type Keychain Access, and open it.
2. In the left sidebar, select login and System under Keychains.
3. Select Certificates under Category.
4. Look for any certificate with your mail server name (for example: mail.YOURDOMAIN).
5. Right‑click the certificate and choose Delete.
6. Enter your Mac password if prompted.

If you don’t see any certificate for your mail server, continue to the next step.

Step 3 — Restart Your Mac

Restarting clears cached trust decisions and prepares Apple Mail to accept the new certificate.

Step 4 — Reopen Mail and Trust the New Certificate

1. Open Mail again.
2. When you see the message “Mail can’t verify the identity of the server…”:
   • Click Show Certificate
   • Check Always trust
   • Click Continue
3. Enter your Mac password if asked.

Apple Mail will now trust the updated RISP mail server certificate.

Step 5 — Verify Your Mail Server Settings

1. In Mail, go to Mail → Settings → Accounts.
2. Select your email account.
3. Under Server Settings, confirm the following:

Incoming Mail (IMAP or POP)

• Server: mail.YOURDOMAIN
• Use TLS/SSL: Enabled
• Authentication: Password

Outgoing Mail (SMTP)

• Server: mail.YOURDOMAIN
• Use TLS/SSL: Enabled
• Authentication: Password

If anything looks different, update it to match the settings above.

Optional: Remove and Re‑Add the Account (IMAP Only)

If the issue continues, removing and re‑adding the account can help.
This does not delete your mail when using IMAP.

1. Go to Mail → Settings → Accounts.
2. Select your account and click – to remove it.
3. Restart your Mac.
4. Add the account again using +.

Optional: Clear Saved Passwords

If Apple Mail keeps trying an old password, it may trigger certificate errors.

1. Open Keychain Access.
2. Search for your email address.
3. Delete any saved passwords for your RISP mail account.
4. Reopen Mail and enter your password again.

Still Having Trouble?

If you continue to receive certificate warnings after completing all steps:

• The certificate update may still be propagating
• Your Mac may need a system update
• There may be a server‑side issue RISP needs to correct

Please open a support ticket and include a screenshot of the error message.