An "authentication failed," "incorrect password," or "login failed" error while setting up email in a desktop or mobile app almost always comes down to one of four things: the username format, the password, the server settings, or a temporary lockout. Work through these in order and the error usually clears up in a few minutes.
1. Use Your Full Email Address as the Username
Most mail apps ask for a "username" field separately from the email address. For a hosted business email account, the username is always your full email address (for example you@yourdomain.com), never just the part before the @ symbol. This is the single most common cause of an authentication error, especially on apps that auto-fill a shortened username.
2. Confirm or Reset the Password
Typos are easy to make on a phone keyboard, and passwords with symbols sometimes get mangled when copied from a note or message. If you are not completely sure the password is correct, reset it directly in your control panel rather than guessing.
In cPanel
- Log in to cPanel and open Email Accounts.
- Find the account and click Manage (or the three-dot menu, depending on your theme).
- Under Security, enter a new password and click Update Email Settings.
In DirectAdmin
- Log in to DirectAdmin and open E-Mail Accounts.
- Click on the email address, or select it and click Modify.
- Enter a new password in the Passwords fields and click Save.
Use the new password in your mail app right away, since the old one stops working the moment you save the change.
3. Check Your Server Settings and Ports
If the username and password are both correct, the next most common cause is a mismatched incoming or outgoing server setting. Use these standard values unless your control panel's email setup page shows different ones for your account:
- Incoming server (IMAP): your domain's mail server, port 993, SSL/TLS enabled.
- Incoming server (POP3): port 995, SSL/TLS enabled.
- Outgoing server (SMTP): port 465 with SSL, or port 587 with STARTTLS.
Both cPanel and DirectAdmin show the exact server name and port numbers for your account on the email account's Connect Devices (cPanel) or Email Settings (DirectAdmin) screen. Copy them directly from there instead of typing them from memory.
Make sure "My outgoing server requires authentication" (or an equivalent toggle) is switched on, using the same full email address and password as the incoming server. A surprising number of authentication errors are actually the outgoing server silently rejecting an unauthenticated connection.
4. Rule Out a Temporary Lockout
Entering the wrong password several times in a row can trigger a short automatic lockout on the mail server, as a protection against brute-force attacks. If you've just corrected a typo and you're still getting rejected, wait 10 to 15 minutes before testing again rather than retrying repeatedly, which can extend the lockout.
If you've confirmed the username, password, and server settings are all correct and the error still won't clear, the mailbox itself may have a deeper delivery or configuration issue. See How to Fix an Email Account That Isn't Sending or Receiving Mail for the next steps.