Create a mailbox and open webmail

You create a mailbox in cPanel under Email Accounts, set its own password and quota, then open Roundcube once to confirm it works. If webmail can send and a reply comes back, the mailbox is fine and any remaining issue is almost always the mail app on the phone or computer.

Create the mailbox in cPanel

In cPanel, open Email Accounts and choose Create. The local part plus your domain becomes the full address, such as [email protected]. That mailbox gets its own password. It is not the cPanel login password, and it is not shared with any other mailbox on the same domain. Mixing those passwords is the most common reason the first phone login fails.

Choose a quota you can live with. Unlimited still counts against the account disk space. If the account is already near full and you leave the mailbox unlimited, new mail can stop while the website still loads. A few gigabytes is enough for most people; give more only if they keep large attachments.

Open Roundcube before you configure any app

From Email Accounts, click Check Email. That opens Roundcube on this stack. Sign in with the full email address and the mailbox password you just set. Send a test message to a second address you control. When a reply lands in Roundcube, delivery and authentication are working.

Roundcube uses the same IMAP store your phone or desktop client will use. If webmail shows the mail and the phone does not, the phone settings are the variable. If Roundcube is empty too, then look at MX records and routing rather than Outlook or Apple Mail.

Settings for the mail app

Use IMAP with the server name mail.example.com (replace example.com with your domain). Inbound is port 993 with TLS. Outbound is port 465 or 587 with TLS. The username is the full email address. The password is the mailbox password, not the cPanel password.

Do not use port 110 or port 25 on the public internet. Many residential ISPs block outbound port 25, and port 110 is cleartext POP. If two devices will share the account, use IMAP on both. POP can split the mailbox across devices. More detail is in our guide on IMAP vs POP.

Keep the cPanel password for cPanel only. Keep the mailbox password for mail. Open Roundcube once to prove the account works, then configure the app. That order avoids a long day of tickets that are not hosting problems.