Can anyone help?

Have been successfully using Windows live mail for nearly 2 years. However, without changing any settings, about every 4 months or so I am unable to login to live mail getting the following error message:

Unable to send or receive messages for the westing25@sky.com 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 [AUTH] Username and password not accepted.
Server: 'pop.tools.sky.com'
Windows Live Mail Error ID: 0x800CCC92
Protocol: POP3
Port: 995
Secure(SSL): Yes

Sometimes if I reset the live mail password this seems to work but not always.

Strangely if I log in to my email thru My Sky while Live Mail is open it seems to jog Live Mail into worrking again.

All suggestions appreciated