POP Checking Fine - SMTP auth failed

[n32]

I've got an odd situation on one of myservers. The pop logins are working fine. I can get emails. But to send out the emails are failing. This is happening with authentication On OR off , whether I use SSL enabled port , or non ssl 25 or secondary 26 port. I've got cpanel ; WHM 10.8.0 cPanel 10.9.0-C107

It is happening on one domain only - I've checked that the configurations are alright, and the details of the accounts are alright. I've used two programs to check ( thunderbird and OE ), and I've deleted the mailbox recreated them. Reset the password as well.

Any tips on where to look ?

[Lyttek]

It'd help if you could explain a bit more what you mean by 'failing'....

Do you get any error messages? Does it not leave your mail client, get stuck on the server, etc...

[n32]

It does not leave the Outlook Express OR Thunderbird mailing client. It does not show any error messages, only a prompt to enter the password. I've reset the password serveral times, made sure no extra white spaces were there, and I've made sure that the info is manually entered and tried different seperators : % + : for the domain and the username.

[n32]

Anyone have any ideas ?