dovecot: imap: Connecting to localhost...failed

[Dan Davison <davison@stats.ox.ac.uk>]

Would someone mind helping me get going with dovecot serving
locally-stored maildir please? I think it's going to be something
simple/stupid, as I haven't got past the first hurdle. The short version
is: I'm using

--8<---------------cut here---------------start------------->8---
(setq gnus-select-method 
      '(nnimap "dc" (nnimap-address "localhost")))
--8<---------------cut here---------------end--------------->8---

and I'm getting

--8<---------------cut here---------------start------------->8---
imap: Connecting to localhost...failed
nnimap (dc) open error: 'nil'.  Continue? (y or n) 
Couldn't open server on dc
--8<---------------cut here---------------end--------------->8---

The long version is below.

Thanks a lot,

Dan


My mail is stored locally in maildir format folders under ~/Maildir, i.e.

--8<---------------cut here---------------start------------->8---
~/Maildir/folder1/{cur,new,tmp}
~/Maildir/folder2/{cur,new,tmp}
...
--8<---------------cut here---------------end--------------->8---

I have email reading under gnus working with

--8<---------------cut here---------------start------------->8---
(setq gnus-select-method '(nnmaildir "email" (directory "~/Maildir/")))
--8<---------------cut here---------------end--------------->8---

but I want to use nnimap. I am trying

--8<---------------cut here---------------start------------->8---
(setq gnus-select-method 
      '(nnimap "dc" (nnimap-address "localhost")))
--8<---------------cut here---------------end--------------->8---

but in the *Messages* buffer I'm getting 

--8<---------------cut here---------------start------------->8---
imap: Connecting to localhost...failed
nnimap (dc) open error: 'nil'.  Continue? (y or n) 
Couldn't open server on dc
--8<---------------cut here---------------end--------------->8---

I'm on ubuntu 9.04 (same problem under 8.10), and have installed
dovecot-common and dovecot-imapd.

I have dovecot running:

--8<---------------cut here---------------start------------->8---
~> ps -u root | grep dovecot
 3302 ?        00:00:00 dovecot
21401 ?        00:00:00 dovecot-auth
--8<---------------cut here---------------end--------------->8---

The only thing I'm changing in the dovecot config file is
mail_location. I've tried two values for that:
--8<---------------cut here---------------start------------->8---
mail_location = maildir:~/Maildir
mail_location = maildir:~/Maildir:LAYOUT=fs
--8<---------------cut here---------------end--------------->8---

And I've tried two folder layout arrangements:

1. ~/Maildir is a single maildir, with ~/Maildir/{cur,new,tmp} and
2. ~/Maildir holds multiple maildirs, i.e.
--8<---------------cut here---------------start------------->8---
~/Maildir/folder1/{cur,new,tmp}
~/Maildir/folder2/{cur,new,tmp}
...
--8<---------------cut here---------------end--------------->8---

I've tried the 4 different possible combinations of those two settings
but get the same error message. I'm using dovecot -n to check that my
dovecot config settings take effect.