Not sure to understand what you call "dial out using OUTLOOK".
I recently was connected to Internet, the connection was OK and I could
surf on the Internet, but I had a problem with mails, even when trying
with different softwares. I had an "IN-USE" error. I have to precise
that usually my mail works perfectly.
I then connected to my mail address using the web interface (after
restarting my Windows session), and it appeared a correspondant had sent
me a message with seven attachments, and the pop protocol had great
difficulties to manage that. The software was still connected, but as
nothing went on the connection, I was not aware of that.
On the web interface, I transfered that message to another "messages
category", so it was no more selected to be downloaded via pop protocol,
as it was no more in the "received messages", and thus the other
messages were downloaded as usual with no problem. I am not sure about
the correct English word about what I called "messages category". A file_?
I stay attentive to answers about knowing which software is locking the
mail account, but please precise your problem, are you connected to
Internet at that moment, and having a problem with just the mail_? Does
it usually work properly_?
Are you able to connect to your mail with telnet for test purposes ?
For this you can need to find a page about pop protocol, supposing this
is the one used on your mail account. The page I know is in French, but
Google will surely give you one in English.