Setup failures.
THE FIRST CHECK
Does webmail work?
If yes, the server is fine and the problem is your client.
WHAT TO CHECK IN THE CLIENT
Username is the full email address Password is the mailbox password, not cPanel Server hostname is correct Ports match the encryption setting Outgoing authentication is enabled
THE MOST COMMON CAUSES
Username without the domain Wrong port for the encryption type Outgoing authentication disabled
WHAT ELSE CAN CAUSE IT
A network blocking mail ports A firewall on your device Too many failed attempts, producing a temporary block
THAT LAST ONE
Repeated wrong-password attempts can block your address temporarily.
Wait, or open a ticket.
WHAT TO TRY
A different network, to rule out network blocking Webmail, to confirm the credentials work
WHAT TO SEND US
The exact error message, the client, and whether webmail works.
