dovecot - Dec 2017 - dovecot (+sendmail) fails to get email into thunderbird

I ain't able to get emails into my email application (thunderbird).

I use 143 Imap to connect which i have tested with telnet and was able to
login. But if i select the inbox with telnet it returns "0 EXISTS"

like so:

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.

My dovecot -n gist.pastebin
<https://gist.github.com/anonymous/db5c7d81e18cff8180f6484c8dcb2a54>

https://gist.github.com/anonymous/db5c7d81e18cff8180f6484c8dcb2a54

Mail location set to: /var/mail/

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Wed, 13 Dec 2017, jo land wrote:
> I use 143 Imap to connect which i have tested with telnet and was able to
> login. But if i select the inbox with telnet it returns "0
EXISTS"
>
> like so:
>
> telnet 192.168.1.13 143
> Trying 192.168.1.13...
> Connected to sub.domain.net.
> Escape character is '^]'.
> 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.
>
> Mail location set to: /var/mail/
Well, /var/mail typically contains a bunch of mbox files, one per local 
users. They are considered an INBOX for each user.

You have configured this for Dovecot:

https://wiki2.dovecot.org/MailLocation/mbox

Each user, that logs in successfully, uses the same files in /var/mail as 
mbox storage. The "INBOX" is empty, because there does not exist 
"/var/mail/inbox", I guess. See 2nd example.

If you see /var/mail/username, you should at least configure 1st example:

# %u is replaced with the username that logs in
mail_location = mbox:~/mail:INBOX=/var/mail/%u

Note the %u and ~ and make sure, each user has an unique home directory. 
You could replace ~ with some specific user-specific path using %u as 
well.

- -- 
Steffen Kaiser
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iQEVAwUBWjIQfMQnQQNheMxiAQIvzggAo4PjphR52C0eHUsKFEojGWaCHPn8gCoA
oIJbuqa9DM2zdbYDvDxHmPYXjnnk8zh2210sd6+wvvpCr13+R1Rbm65oXfi++zgk
AUu7d/NB+wULafRxl+NY2HQNVDG1dk/1eHhDijmDDqF9A4eKYNjvHhZbRyQ7gEMw
CwBOne8R8uP+pWiFjDMyvPJObjFrGflxlwVgqopbEBq7WM6cCx96esY4sJVJzG/B
NN9PMHsmPdysngTXlE7DzzCrRrTzuccXCHD40AKh5n8Q5/HKHvl3egvQY/I6x21J
jYCEEEGTG0vN8kVQDKSXD0Q0l+yYq1hA6VYpsKS4CI8kL0UpRRo0jA==yetO
-----END PGP SIGNATURE-----

> # %u is replaced with the username that logs in
> mail_location = mbox:~/mail:INBOX=/var/mail/%u
>
if i change the mail location into: mbox:~/mail:INBOX=/var/mail/%u

mail.log says:

Dec 14 14:24:26 pie dovecot: imap(update.site1): Error: user update.site1:
Initialization failed: Namespace '': mbox: mbox root directory can't
be a
file: /var/spool/mail/mail