Android mail setup differs from iOS in one important way: there is no single Mail app. Gmail, Outlook, Samsung Email and a dozen others are all in use, each with its own wording and its own defaults. The settings are identical everywhere; only the labels move.
This covers the settings, then the two places Android apps commonly differ from what you expect.
The settings, wherever you enter them
Take them from cPanel rather than guessing: Email Accounts, then Connect Devices for the mailbox:
Host mail.yourdomain.com IMAP 993, SSL/TLS SMTP 465 SSL/TLS, or 587 STARTTLS Username the full address, [email protected]
The username is the complete address. This is the most common cause of a rejected password across every Android app, because several of them label the field "Username" and people fill in a username.
Adding it in Gmail
Gmail is on most Android phones, so it is where most people end up.
Open Gmail, tap your avatar, then Add another account. Choose Other: not any of the named providers, none of which apply to a cPanel mailbox.
Enter the full address and tap Manual setup rather than Next. Choose Personal (IMAP).
Enter the password, then the incoming server settings, then the outgoing settings. On the outgoing screen make sure Require sign-in is enabled and that the username there is the full address again, some versions leave it blank when moving between screens.
That last point is the Android equivalent of the setting people miss: receiving works, sending fails with a vague error, and the outgoing credentials are empty.
Other apps
Outlook for Android, Samsung Email and the rest follow the same shape. Look for an option named Other, Manual setup, or Advanced. Anything that avoids the app choosing settings for you.
If an app cannot be made to accept manual IMAP settings, it is the wrong app for this mailbox. Gmail and Outlook both handle it well.
Battery optimisation stops mail syncing
This is the Android-specific problem, and it is the reason behind most reports of mail arriving late on Android and not on other devices.
Android restricts background activity for apps it considers idle. A mail app under battery optimisation stops checking, and mail then appears only when the app is opened, which looks exactly like a broken account.
Exempt the mail app from battery optimisation in the phone's app settings. The wording differs by manufacturer: Unrestricted, Not optimised, Allow background activity.
Some manufacturers add a second layer of their own power management on top, with its own list. If mail still only arrives when the app is opened after exempting it in the standard place, look for the manufacturer's own battery settings.
Sync frequency
Each account has its own sync interval, usually in the account settings under Sync frequency or Check frequency.
Every 15 minutes is a sensible default. Setting it to manual means mail only arrives when you open the app, and people forget they chose that.
Also check how much mail is synced. Many apps default to a few days or a month, which makes older mail invisible on the phone even though it exists on the server. That is a setting instead of a fault.
Deleting the account is safe
With IMAP, mail lives on the server, so removing the account from the phone deletes nothing and re-adding downloads it again.
That makes remove-and-re-add a reasonable first fix, and it resolves a fair share of Android mail problems that resist explanation: particularly after an app update.
Common failures
Password rejected. The username is not the full address. This is the answer most of the time.
Cannot connect to server. Check the hostname, then try the other outgoing port, mobile networks block ports unpredictably and 587 often works where 465 does not.
Receives but cannot send. Require sign-in is off, or the outgoing username was left blank between setup screens.
Works on wifi, fails on mobile data. The mobile network is blocking the port. Switch between 465 and 587.
Mail only arrives when the app is opened. Battery optimisation, or sync set to manual.
Certificate warning, app offers to accept it. Do not accept a certificate you were not expecting. Use the exact hostname from cPanel instead.
Mail is in webmail but not on the phone. The mailbox is fine and the app is not syncing that folder. Accessing webmail goes into using it to work out which side the fault is on.
Check the device is not the problem
Mail configuration on a phone is reported as broken more often than it is, and the usual causes are local. A device with no connection, a battery saving mode that stops background fetching, or a system update that reset the account each produce symptoms indistinguishable from a server fault. Confirm the same account works in webmail from a browser first. If mail is there, the mailbox and the server are fine and the entire investigation belongs to the device, which saves changing settings that were correct.