I'm on Ubuntu 10.10 (Maverick) with mutt:
Mutt 1.5.20 (2009-06-14)

Started getting this when switching to a new MS Exchange-2010 server using imap from an older exchange server
It happens very frequently making mutt very unusable.

      tls_socket_read (A TLS packet with unexpected length was received)

$ mutt -v
Mutt 1.5.20 (2009-06-14)
Copyright (C) 1996-2009 Michael R. Elkins and others.
Mutt comes with ABSOLUTELY NO WARRANTY; for details type `mutt -vv'.
Mutt is free software, and you are welcome to redistribute it
under certain conditions; type `mutt -vv' for details.

System: Linux 2.6.35-28-generic (x86_64)
ncurses: ncurses 5.7.20100626 (compiled with 5.7)
libidn: 1.18 (compiled with 1.18)
hcache backend: GDBM version 1.8.3. 10/15/2002 (built Dec  5 2009 22:15:17)
Compile options:
-DOMAIN
+DEBUG
-HOMESPOOL  +USE_SETGID  +USE_DOTLOCK  +DL_STANDALONE  +USE_FCNTL  -USE_FLOCK   
+USE_POP  +USE_IMAP  +USE_SMTP  
-USE_SSL_OPENSSL  +USE_SSL_GNUTLS  +USE_SASL  +USE_GSS  +HAVE_GETADDRINFO  
+HAVE_REGCOMP  -USE_GNU_REGEX  
+HAVE_COLOR  +HAVE_START_COLOR  +HAVE_TYPEAHEAD  +HAVE_BKGDSET  
+HAVE_CURS_SET  +HAVE_META  +HAVE_RESIZETERM  
+CRYPT_BACKEND_CLASSIC_PGP  +CRYPT_BACKEND_CLASSIC_SMIME  +CRYPT_BACKEND_GPGME  
-EXACT_ADDRESS  -SUN_ATTACHMENT  
+ENABLE_NLS  -LOCALES_HACK  +COMPRESSED  +HAVE_WC_FUNCS  +HAVE_LANGINFO_CODESET  +HAVE_LANGINFO_YESEXPR  
+HAVE_ICONV  -ICONV_NONTRANS  +HAVE_LIBIDN  +HAVE_GETSID  +USE_HCACHE  
-ISPELL
SENDMAIL="/usr/sbin/sendmail"
MAILPATH="/var/mail"
PKGDATADIR="/usr/share/mutt"
SYSCONFDIR="/etc"
EXECSHELL="/bin/sh"
MIXMASTER="mixmaster"
To contact the developers, please mail to <email address hidden>.
To report a bug, please visit http://bugs.mutt.org/.

misc/am-maintainer-mode
misc/hg.pmdef.debugtime
debian-specific/build_doc_adjustments.diff
features/ifdef
features/xtitles
features/trash-folder
features/purge-message
features/sensible_browser_position
features-old/patch-1.5.4.vk.pgp_verbose_mime
features/compressed-folders
features/compressed-folders.debian
debian-specific/Muttrc
debian-specific/Md.etc_mailname_gethostbyname.diff
debian-specific/use_usr_bin_editor.diff
debian-specific/correct_docdir_in_man_page.diff
debian-specific/dont_document_not_present_features.diff
debian-specific/document_debian_defaults
debian-specific/assumed_charset-compat
debian-specific/467432-write_bcc.patch
misc/define-pgp_getkeys_command.diff
misc/gpg.rc-paths
misc/smime.rc
upstream/533209-mutt_perror.patch
upstream/533459-unmailboxes.patch
upstream/533439-mbox-time.patch
upstream/531430-imapuser.patch
upstream/534543-imap-port.patch
upstream/538128-mh-folder-access.patch
upstream/537818-emptycharset.patch
upstream/535096-pop-port.patch
upstream/542910-search-segfault.patch
upstream/533370-pgp-inline.patch
upstream/533520-signature-highlight.patch
upstream/393926-internal-viewer.patch
upstream/543467-thread-segfault.patch
upstream/544180-italian-yesorno.patch
upstream/542817-smimekeys-tmpdir.patch
upstream/544794-smtp-batch.patch
upstream/537694-segv-imap-headers.patch
upstream/548577-gpgme-1.2.patch
upstream/548494-swedish-intl.patch
upstream/553321-ansi-escape-segfault.patch
upstream/553238-german-intl.patch
upstream/557395-muttrc-crypto.patch
upstream/545316-header-color.patch
upstream/568295-references.patch
upstream/547980-smime_keys-chaining.patch
upstream/528233-readonly-open.patch
upstream/228671-pipe-mime.patch
upstream/383769-score-match.patch
upstream/547739-manual-typos.patch
upstream/311296-rand-mktemp.patch
upstream/573823-imap_internal_date
upstream/542344-dont_fold_From_
upstream/path_max
misc/hyphen-as-minus.patch
misc/smime_keys-manpage.patch
mutt.org