IMAP to Exchange hangs: NO Connect filed: server may be down or too busy to respond

IMAP to Exchange hangs: NO Connect filed: server may be down or too busy to respond

[Chris Shenton]

I've been forced to use an Exchange server at work, and config Gnus to
access via IMAPS.  I had this working the past couple weeks but today
I can't retrieve mail reliably. I've got a bunch of folders and saved
mail there, maybe 200 folders and 300MB of mail.  I see it "Reading
active file...", and such for a while, then it hangs; after 30 minutes
or something it eventually says "IMAP process not running" or
something similar.

Here's what I see in the *imap-debug* buffer:

| | | | | | 7 <- imap-arrival-filter: nil
| | | | | | 7 -> imap-arrival-filter: proc=#<process imap> string="308 NO Connect attempt failed: server may be down or too busy to respond.

The last entries in *nnimap-debug* are:

1 -> nnimap-retrieve-groups: groups=("INBOX/in/shenton@hq" 
...
"INBOX/list/wireless-eng@spinoza.public.hq.nasa.gov") server="hemi"
| 2 -> nnimap-possibly-change-server: server="hemi"
| 2 <- nnimap-possibly-change-server: " *nnimap* hemi"
| 2 -> nnimap-before-find-minmax-bugworkaround: 
| 2 <- nnimap-before-find-minmax-bugworkaround: nil
| 2 -> nnimap-find-minmax-uid: group="INBOX/list/wireless-eng@spinoza.public.hq.nasa.gov" examine=examine

And that folder name is what it's displaying on the mode line while
it's hung. 

Here's my server config:

(setq gnus-select-method
      '(nnimap "hemi"                ; use ~/.authinfo for user/passwd
               (nnimap-address "mail01.ndc.nasa.gov")
               (nnimap-stream ssl) ))

I'm using No Gnus v0.4 from December, and just tried with a version
slurped from CVS, same problem.

Any suggestions on what I can do here? If the problem is the server
complaining about overload, can Gnus recover from this status?

I'm not having problems reading from the same server with OS X Tiger's 
Mail.app nor with Mozilla's Mail pane.

Thanks.

Re: IMAP to Exchange hangs: NO Connect filed: server may be down or too busy to respond

[Chris Shenton]

I've been poking through *imap-debug* trying to find what's causing
the hang.  The IMAP command that appears to be generating the "NO"
response from Exchange is:

| | 3 -> imap-send-command-1: cmdstr="302 STATUS \"Public Folders/Aelita EMW Recycle Bin\" (uidvalidity uidnext unseen)"
| | 3 <- imap-send-command-1: nil
| 2 <- imap-send-command: 302

and eventually it gets this response:

| | | | | | 7 -> imap-arrival-filter: proc=#<process imap> string="302 NO Connect attempt failed: server may be down or too busy to respond."

So I tried connecting to the same mailbox using OS X Mail.app.  It
spins for a while when I try to enter the group, then grays out the
mailbox name. Hovering over it shows a tooltip that says: 

  Mail was unable to open this mailbox on server ...

and shows the same "too busy" message as above.

So there's something hosed with the Exchange server (surprise!) but
Mail.app recovers gracefully why Emacs does not.

I've tried to make it avoid anything but the INBOX tree using
nnimap-list-pattern as below:

  (setq gnus-select-method
      '(nnimap "hemi"                ; use ~/.authinfo for user/passwd
             (nnimap-address "mail01.ndc.nasa.gov")
             (nnimap-stream ssl)
             (nnimap-list-pattern ("INBOX"))
             ))

but *imap-log* is still showing it querying other mailbox hierarchies
including the broken one, 302 below:

  301 STATUS "INBOX/saved/zope" (uidvalidity uidnext unseen)
  302 STATUS "Public Folders/Aelita EMW Recycle Bin" (uidvalidity uidnext unseen)
  303 STATUS "Public Folders/Internet Newsgroups" (uidvalidity uidnext unseen)
  ...
  301 OK STATUS completed.
  302 NO Connect attempt failed: server may be down or too busy to respond.


Is gnus ignoring the list-pattern or am I missing something?

And is there a way to get gnus to recover from the "NO" response about
a group? 

Thanks.

Re: IMAP to Exchange hangs: NO Connect filed: server may be down or too busy to respond

[Simon Josefsson]

Chris Shenton <chris@shenton.org> writes:

> I've tried to make it avoid anything but the INBOX tree using
> nnimap-list-pattern as below:
>
>   (setq gnus-select-method
>       '(nnimap "hemi"                ; use ~/.authinfo for user/passwd
>              (nnimap-address "mail01.ndc.nasa.gov")
>              (nnimap-stream ssl)
>              (nnimap-list-pattern ("INBOX"))
>              ))
>
> but *imap-log* is still showing it querying other mailbox hierarchies
> including the broken one, 302 below:
>
>   301 STATUS "INBOX/saved/zope" (uidvalidity uidnext unseen)
>   302 STATUS "Public Folders/Aelita EMW Recycle Bin" (uidvalidity uidnext unseen)
>   303 STATUS "Public Folders/Internet Newsgroups" (uidvalidity uidnext unseen)
>   ...
>   301 OK STATUS completed.
>   302 NO Connect attempt failed: server may be down or too busy to respond.
>
>
> Is gnus ignoring the list-pattern or am I missing something?

Are you subscribed to that particular group?  Try C-k it.

> And is there a way to get gnus to recover from the "NO" response about
> a group? 

I agree that it should recover more gracefully.  Patches welcome...
I'm not sure how it could be implemented though.

Re: IMAP to Exchange hangs: NO Connect filed: server may be down or too busy to respond

[Chris Shenton]

Simon Josefsson <jas@extundo.com> writes:

> Are you subscribed to that particular group?  Try C-k it.

Yeah, I (stupidly) edited the .newrc.eld file since I couldn't get
gnus to come back after hanging.

> I agree that it should recover more gracefully.  Patches welcome...
> I'm not sure how it could be implemented though.

I was looking at imap.el starting with imap-arrival-filter,
imap-parse-response, but I quickly realized I'm not smart enough to
understand it.  

If anyone has pointers on how I might approach this I'd be willing to
give it a try. 

Thanks.