pop client will not accept password

pop client will not accept password - Fix A Problem | Google Groups:

"Hello Wing Lee,

There are several possibilities for what is causing this:
1) Make sure they are using their usern...@mydomain.com and their
GApps account password.

2) Try removing the pop3 account in the client email application and
re-adding it

3) If an anti-virus program is running, trying turning it off during
the connection just to see if there is an issue with it interrupting
the flow. If this resolves the problem then you might have to play
with the configuration for the anti-virus.

4) Check the configuration instructions carefully for the client.
You don't want to have the box checked 'Require logon using Secure
Password Authentication (SPA)

Larry - Power Poster"