imap proxy not authenticating

[DuddiZetor]

Hi,

I have a new multi-server setup with 5 servers (1 ldap, 1 mta, 1 proxy and 2 mailbox servers). All running: Release 8.7.5.GA.1764.UBUNTU16.64 UBUNTU16_64 NETWORK edition.

And I have a strange problem in that POP3 logins work but not IMAP login. Here is excerpt from nginx.log (set to mail_debug):
IMAP:
2017/11/29 12:11:29 [info] 806#0: *6 client x.x.x.54:36830 connected to 0.0.0.0:143
2017/11/29 12:11:29 [debug] 806#0: *6 imap auth state
2017/11/29 12:11:29 [debug] 806#0: *6 imap auth command: 3
2017/11/29 12:12:29 [debug] 806#0: *6 imap auth state
2017/11/29 12:12:29 [info] 806#0: *6 client timed out (110: Connection timed out) while in auth state, client: x.x.x.54:36830, server: 0.0.0.0:143
2017/11/29 12:12:29 [debug] 806#0: *6 close mail connection: 17

POP3:
2017/11/29 12:13:48 [info] 1546#0: *5 client x.x.x.54:33331 connected to 0.0.0.0:110
2017/11/29 12:13:48 [debug] 1546#0: *5 pop3 auth state
2017/11/29 12:13:48 [debug] 1546#0: *5 pop3 login: "xxx@x.x"
2017/11/29 12:13:48 [debug] 1546#0: *5 pop3 auth state
2017/11/29 12:13:48 [debug] 1546#0: *5 mail cleanup add: 0000000000E1DBB8
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy pop3 auth handler
2017/11/29 12:13:48 [debug] 1546#0: *5 sending POP3 XOIP command (XOIP x.x.x.54)
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy pop3 auth handler
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy dummy handler
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy pop3 auth handler
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy send user
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy dummy handler
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy pop3 auth handler
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy send pass
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy dummy handler
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy pop3 auth handler
2017/11/29 12:13:48 [info] 1546#0: *5 client logged in, client: x.x.x.54:33331, server: 0.0.0.0:110, login: "xxx@x.x", upstream: x.x.x.67:7995 (x.x.x.54:33331->x.x.x.69:110) <=> (x.x.x.69:43968->x.x.x.67:7995)
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 1, #15 > #14
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 1, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #15 > #14
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 1, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #15 > #14
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 1, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #15 > #14
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 1, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #15 > #14
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 1, #14 > #15
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #15 > #14
2017/11/29 12:13:48 [debug] 1546#0: *5 mail proxy handler: 0, #14 > #15
2017/11/29 12:13:48 [info] 1546#0: *5 proxied session done, client: x.x.x.54:33331, server: 0.0.0.0:110, login: "xxx@x.x", upstream: x.x.x.67:7995 (x.x.x.54:33331->x.x.x.69:110) <=> (x.x.x.69:43968->x.x.x.67:7995)
2017/11/29 12:13:48 [debug] 1546#0: *5 close mail proxy connection: 15
2017/11/29 12:13:48 [debug] 1546#0: *5 close mail connection: 14

I have checked zm_lookup_handlers, looks ok:
zm_lookup_handlers https://x.x.x.67:7072/service/extension/nginx-lookup https://x.x.x.70:7072/service/extension/nginx-lookup;

Here is IP info
.67 is mailbox01
.69 is proxy01
.70 is mailbox02

I have searched all over the forums and the web for info, not found a solution. Here is a similar problem, but does not work for me: viewtopic.php?t=60367

Thanks