I have 5 Optusnet email accounts, 3 of which work perfectly but with the other 2 I can neither send nor receive emails.

This has happened since the initial setup 2 days ago, when all 5 accounts were added at the same time. 

The usernames and passwords are correct, and the settings are exactly the same as the 3 working email accounts.

I'm using Windows Live Mail 2012 on Windows 10.

This is the error message I receive:

Unable to send or receive messages for the Optusnet.com (xxxxx) account. An incorrect password was entered. The next time you send or receive messages, you'll be asked to enter your user name and password for this account.

Server Error: 0x800CCC90
Server Response: -ERR Authentication failed.
Server: 'mail.optusnet.com.au'
Windows Live Mail Error ID: 0x800CCC92
Protocol: POP3
Port: 110
Secure(SSL): No

I seriously need help on this matter and your input would be greatly appreciated.