Offlineimap unknown SSL protocol error

Question

I am using offlineimap to fetch mail from several IMAP servers. This used to work but today offlineimap has been unable to fetch mail, producing the following errors:

*** Processing account example
 Establishing connection to imap.gmail.com:993
 ERROR: Unknown SSL protocol connecting to host 'imap.gmail.com' for
 repository '<redacted>'. OpenSSL responded:
 [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:590)
*** Finished account 'example' in 0:00

Relevant parts of my configuration are:

[Account example]
localrepository  =  local-example
remoterepository = remote-example

[Repository local-example]
type = Maildir
localfolders = ~/mail/example

[Repository remote-example]
maxconnections = 1
type = Gmail
remotehost = imap.gmail.com
remoteuser = [email protected]
remotepasseval = get_keychain_pass(account="[email protected]",
                                   server="imap.gmail.com")
ssl = yes
sslcacertfile = /usr/local/etc/openssl/certs/dummycert.pem

The sslcacertfile configuration was created in response to this SO answer. The get_keychain_pass function is from this offlineimap configuation.

I am using offlineimap 6.5.7 built with Homebrew on OS X 10.10.4.

Answer 1

The problem started when I installed Homebrew's version of python rather than the Apple version. The error was resolved by running

brew uninstall python

I discovered this was the solution by reading about a similar error produced by another Python program on OS X.

Answer 2

I have a need for both the Apple and Homebrew versions of Python installed. Some packages I need to install from pip, and I do not have administrative access to this work-issued Macbook Pro. Thus the only pip I have available to me is for Homebrew. What I ended up doing is set the following PYTHONPATH before launching the offlineimap.py script:

PYTHONPATH="/Library/Python/2.7/site-packages" exec "/Users/tblancher/homebrew/Cellar/offlineimap/7.0.7/libexec/offlineimap.py" "$@"

I also modified the offlineimap.py script itself. I changed the first line, from this:

#!/usr/bin/env python

To this:

#!/usr/bin/python

Apparently env was picking up that it was in Homebrew, and therefore trying to use the Homebrew python. Offlineimap now works correctly, and so does my Homebrew-pip-installed Python package (mutt-ics, if you're curious).