IMAP reconnection fails

[Jessica Perry Hekman <jphekman@xxxxxxxxxxxx>]

Hi all. Continuing in my quest to move to mutt from pine...

I save my archived mail remotely and access it via IMAP. (For that matter 
I access my inbox via IMAP, but a different server.) In my .muttrc:

set folder="imaps://machinename.net/mail"
set spoolfile="{other.machinename.com}../mail/INBOX"
set imap_user="jphekman"
set ssl_starttls=yes
set certificate_file=~/.mutt/certificates

When I try to view or save to a remote folder, mutt lets me log in to
machinename.net. When I try to view/save again, things just work. All
good. But if I wait a while and then try to view those folders, mutt says
"Getting folder list" and hangs. I presume that what is happening is that
it has lost its IMAP connection to that machine and is failing to
reconnect for some reason.

I have been googling this issue without much success. At one point I found 
a reference on a mailing list to a fix in the code base, so I downloaded 
the latest (mutt-1.4.2.1i) and built that; same problem.

Can anyone shed any light?

Thanks,

Jessica