'network password' request box

[pamela]

i keep having a box pop up (3-12 times an hour) while in
outlook2k3, entitled "Enter Network Password", which
asks: 'Please type your user name and password', and then
are listed my server (outgoing.verizon.net), my user name
(pamela), and my password (*************) [and i'm given
to option of checking the box to save this password in my
password list.]

i've checked my settings for two different accounts, and
both are correct.

any ideas of the source of this query???? thanks!!