It's not behind a proxy (unless the router is acting as a proxy?). Could it be that my router is doing some Hairpin NAT tomfoolery? The router is generic, so I run into that from time to time with my webserver.

I tried doveadm who, but didn't see anything too peculiar. There is the expect half dozen or so users on common IPs.

On 27.02.20 21:49, Aki Tuomi wrote:
Is your server behind proxy maybe? Can you see in logs that you get different IPs? 

Maybe check with `doveadm who` how many connections you have?

Aki
On 27/02/2020 22:44 Esteban L < esteban@little-beak.com> wrote:


I have tried a lot of different things, still no success. =(

here is my dove -n if anyone could help that would be great:


# 2.2.27 (c0f36b0): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.16 (fed8554)
# OS: Linux 4.9.0-12-amd64 x86_64 Debian 9.12
auth_debug = yes
auth_debug_passwords = yes
auth_mechanisms = plain login
auth_verbose = yes
auth_verbose_passwords = yes
mail_home = /var/mail/vmail/%d/%n
mail_location = maildir:~/Mail
mail_max_userip_connections = 500
mail_plugins = " quota"
mail_privileged_group = vmail
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope
encoded-character vacation subaddress comparator-i;ascii-numeric
relational regex imap4flags copy include variables body enotify
environment mailbox date index ihave duplicate mime foreverypart extracttext
namespace inbox {
  inbox = yes
  location =
  mailbox Archive {
    auto = subscribe
    special_use = \Archive
  }
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  prefix =
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
plugin {
  quota = maildir:User quota
  quota_grace = 10%%
  quota_rule = *:storage=10G
  quota_rule2 = Trash:storage=+1G
  quota_status_overquota = 552 5.2.2 Mailbox is full
  quota_warning = storage=95%% quota-warning 95 %u
  quota_warning2 = storage=80%% quota-warning 80 %u
  sieve = ~/.dovecot.sieve
  sieve_after = /etc/dovecot/sieve/spamfilter.sieve
  sieve_dir = ~/sieve
}
protocols = " imap lmtp sieve"
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0666
    user = postfix
  }
}
service imap-login {
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
}
ssl = required
ssl_cert = </etc/letsencrypt/live/little-beak.com/fullchain.pem
ssl_key =  # hidden, use -P to show it
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
protocol lmtp {
  mail_plugins = " quota sieve"
  postmaster_address = *****@little-beak.com
}
protocol lda {
  mail_plugins = " quota sieve"
}
protocol imap {
  mail_max_userip_connections = 500
  mail_plugins = " quota imap_quota"
}
protocol sieve {
  mail_max_userip_connections = 500
}


On 27.02.20 18:54, Esteban L wrote:
I have been haunted by the following error message or months, that we
see using Thunderbird.
Unable to connect to your IMAP server.
You may have exceeded the maximum number of connections to this server.
If so, use the Advanced IMAP Server Settings dialogue to reduce the
number of cached connections.
If I change my location, via a VPN, the error message goes away and I
can connect.
I have edited my /etc/dovcot/conf.d/20-imap.conf file by adding the
following:
>
protocol imap {
  # Space separated list of plugins to load (default is global
mail_plugins).
  mail_plugins = $mail_plugins imap_quota
  # Maximum number of IMAP connections allowed for a user from each IP
address.
  # NOTE: The username is compared case-sensitively.
  mail_max_userip_connections = 500
}
>
And, I still get the error message. I know myself, I have about 8-9
accounts, some with as many as 10 folders (I know each one count's as
it's own mailbox), as does my partner--who would access the internet
from my IP.
Does that number really have to be like 10,000, or something? If so, why
does it start out so small in the first place. If not, what else could I
do to avoid this message going forward??
>
>
>

---
Aki Tuomi