Good Day, I am not able to send mail from one of my accounts. I'm running Windows 8.1 with Windows Live Mail. Upon sending mail

I am continually asked to enter the password for the account but when I do I an presented with the same pop-up!

I have checked all my POP3 setting quite a few times and I have had a BELL Canada technician remotely attempt to correct the problem but failed.

Whenever I go to properties for the account and click on the Servers Tab then the Advance Tab the setting for "requires password" has a check mark. I remove the checkmark and select the top option then Apply & OK. I then re-open the Properties window and find the check box to select "ask for a password" has a tick in it...again.  That's why I keep getting asked for a password when sending !! Anyone know what the heck is happening? My other email account works fine. E.L.