I saw a bunch of changes in CVS for imp, so I tried it again. Not sure 
what happened, but it seems to be fixed.

Ignore the blank page error. That was due to a popup blocker.



1) No custom login page.



2) Horde auth settings:



$servers['imap'] = array(

     'name' => 'The Server',

     'server' => 'localhost',

     'hordeauth' => false,

     'protocol' => 'imap/notls',

     'port' => 143,

     'maildomain' => 'domain.dlt',

     'smtphost' => 'localhost',

     'smtpport' => 25,

     'realm' => '',

     'preferred' => '',

);

#1 - are you using a custom login page?

#2 - What are your hordeauth settings (in imp/config/servers.php) for 
the server you are using?

More information: $imapuser contains "@domain.tld" (for my domain.) 
However, $_SESSION['imp']['user'] conatins "username@domain.tld". 
Those aren't equal, so it's failing.



Another issue, perhaps this is related, but under the Safari browser, 
clicking on "INBOX" results in an empty frame. This happens if one 
clicks on any folder, but clicking on "Mail" with those lines removed 
works. The blank page also happens under horde 3.1.1 as well, but 
clicking on "Mail" works in that version.

I mean "is true". So, apparently "$imapuser != 
$_SESSION['imp']['user']" is true. Any thing else I can test?

Apparently, it's: ($imapuser !== null && ($imapuser != 
$_SESSION['imp']['user']))



Then from there, it is "$imapuser !== null" if true.

It would help if you could tell us which case matched to fall through 
to that unset() code.  i.e., which of the following cases:



     if (($imapuser !== null && ($imapuser != $_SESSION['imp']['user'])) ||

         ($pass !== null && ($pass != 
Secret::read(Secret::getKey('imp'), $_SESSION['imp']['pass'])))) {



matches.

I searched all of imp for logout. I found two in redirect.php. 
Commenting out lines 96 & 97:



         #unset($_SESSION['imp']);

         #_redirect(Auth::addLogoutParameters(IMP::logoutUrl(), 
AUTH_REASON_FAILED));



Caused it to work now.

We are going to need a lot more information to do anything about this. 
  Like where exactly in the code is is kicking you out as 
unauthenticated.

I should clarify: it's not just when you first login, as I thought 
originally. It's every time. The released horde/imp do not have this 
problem.

I'm using imp for horde login to an imap server. However, when I click 
on the Mail icon in the sidebar, I get "Login failed" and another 
login screen. My server's logs report that the new user logged in 
successfully each time. This happens in Firefox and Safari for the Mac.



I can open a specific folder if I open the Mail tree in the sidebar, 
and that works. I can even click on "Inbox" and the virtual inbox and 
things work OK. Just not the Mail tree base in the sidebar.



It also doesn't seem to really logout, since I can just enter the base 
URL for horde and I'm back logged in, although the mail tree in the 
sidepanel is now empty.