dovecot (+ sendmail) não consegue enviar e-mail para o Thunderbird

Question

Não consigo enviar e-mails para meu aplicativo de e-mail (Thunderbird).

Eu uso 143 Imap para conectar, que testei com telnet e consegui fazer login. Mas se eu selecionar a caixa de entrada com telnet ele retornará "0 EXISTS"

igual a:

telnet 192.168.1.13 143
Trying 192.168.1.13...
Connected to sub.domain.net.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN] Dovecot ready.
oper1 login update.site1 1234
oper1 OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS MULTIAPPEND     UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS     SPECIAL-USE] Logged in
oper2 select INBOX
* FLAGS (\Answered \Flagged \Deleted \Seen \Draft)
* OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \*)] Flags permitted.
* 0 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1513093097] UIDs valid
* OK [UIDNEXT 1] Predicted next UID
* OK [NOMODSEQ] No permanent modsequences
oper2 OK [READ-WRITE] Select completed.

Meu pombal -n essência.pastebin

Local de correio definido como: /var/mail/