Configuration is not working with Thunderbird

[Quark]

Hi, I'm new to the list (and postfix / dovecot), so if I mistakenly omit 
something, then please forgive me.

I cannot log into Thunderbird via IMAP with my configuration. However, I 
can check the mail of each user by logging into their user account & 
then using the "mail" command.  Is there something that is wrong with my 
config to not allow me to log into Thunderbird (Version 52.1.1)?  I'm 
using Postfix 3.1.0 if that helps.  Any help would be greatly 
appreciated.  Thanks!

Here is the output of "|dovecot -n"|:

# 2.2.22 (fe789d2): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.13 (7b14904)
doveconf: Warning: NOTE: You can get a new clean config file with: 
doveconf -n > dovecot-new.conf
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:105: 
listen=..:port has been replaced by service { inet_listener { port } }
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:105: 
protocol { listen } has been replaced by service { inet_listener { 
address } }
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:106: 
ssl_listen=..:port has been replaced by service { inet_listener { port } }
doveconf: Warning: Obsolete setting in /etc/dovecot/dovecot.conf:106: 
protocol { ssl_listen } has been replaced by service { inet_listener { 
address } }
# OS: Linux 4.4.0-77-generic x86_64 Ubuntu 16.04.2 LTS
mail_location = maildir:~/Maildir
namespace inbox {
   inbox = yes
   location =
   mailbox Drafts {
     special_use = \Drafts
   }
   mailbox Junk {
     special_use = \Junk
   }
   mailbox Sent {
     special_use = \Sent
   }
   mailbox "Sent Messages" {
     special_use = \Sent
   }
   mailbox Trash {
     special_use = \Trash
   }
   prefix =
}
passdb {
   driver = pam
}
protocols = imap
service imap-login {
   inet_listener imap {
     address = *
     port = 143
   }
   inet_listener imaps {
     address = *
     port = 993
   }
}
ssl_cert = </etc/letsencrypt/live/REDACTED/fullchain.pem
ssl_key = </etc/letsencrypt/live/REDACTED/privkey.pem
userdb {
   driver = passwd
}
protocol imap {
   imap_client_workarounds = tb-extra-mailbox-sep
}