linux - Mutt email client not receiving or sending mail

I am trying to setup the mutt email client on my Linux system, however, I am running into some issues.

To begin with, when Mutt launches it states the following at the bottom of the screen: gnutls_handshake: An unexpected TLS packet was received. When I go to send an email (to myself for testing purposes) and input my login information mutt states that it's logging in but the Logging in... message only stays on the screen for a split second and afterwards nothing happens (no email is sent).

Here is my .muttrc file:

## IMAP CREDENTIALS
set smtp_url = "smtp://jacksewell@smtp.kolabnow.ch:587/"
#set smtp_pass = "password"
set from = "jacksewell@kolabnow.ch"
set realname = "Jack Sewell"
## IMAP SETTINGS
# activate TLS if available on the server
set ssl_starttls=yes
# always use SSL when connecting to a server
set ssl_force_tls=yes
# Don't wait to enter mailbox manually
unset imap_passive
# Automatically poll subscribed mailboxes for new mail (new in 1.5.11)
set imap_check_subscribed
set folder = "imaps://imap.kolabnow.ch:993"
set spoolfile = "+INBOX"
## GENERIC
set header_cache=~/.mutt/cache/headers
set message_cachedir=~/.mutt/cache/bodies
set certificate_file=~/.mutt/certificates
# Move read messages from your spool mailbox to your $mbox mailbox
set move = no
# Reduce polling frequency to a sane level
set mail_check=60
# And poll the current mailbox more often (not needed with IDLE in post 1.5.11)
set timeout=10
# keep a cache of headers for faster loading (1.5.9+?)
set header_cache=~/.hcache
# Display download progress every 5K
set net_inc=5
# Don't switch to next mail when paging down in a mail and hitting bottom
set pager_stop=yes
# Confirm quit
set quit=ask-yes
# Date format in index view. Standard strftime syntax.
set date_format="!%a, %b %d, %Y at %I:%M:%S%p %Z"
# Default index format
#set index_format="%4C %Z %{%b %d} %-15.15L (%?l?%4l&%4c?) %s"
set index_format="%4C %Z %{%b %d %H:%M}  %-15.15L (%?l?%4l&%4c?) %s"