ERR_CONNECTION_REFUSED accessing PMG web interface or Exchange OWA from Chrome

HAProxy version 2.4.22-0ubuntu0.22.04.3

Proxmox Mail Gateway behind it.

All works fine, but suddenly started getting an error “ERR_CONNECTION_REFUSED” in any browser at some PCs of my copmpany. Some PCs works well howerever.
At the same time if i open the PMG by IP it works well.

Please help me resolve this issue or teach me please how to find the reason of that error?

Thanks in advance.

UPD: actually i have Exchange 2019 behind the Haproxy too. And from time to time some PCs can’t access OWA with the exactly same error.
Help needed. Thanks.

image

Any help?

No one?

Please provides some HAProxy logs, it’s difficult to know what’s going on with just a browser screenshot, that could be anything like your firewall or your computer.

Actually, I’m not familiar with haproxy logging. All i saw when the error repeated:

Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56356 [17/Jun/2024:17:35:23.312] fe_ex2019~ be_ex2019_mapi/exch01 0/0/2/10/12 401 514 - - ---- 47/47/38/38/0 0/0 "POST /mapi/nspi/?MailboxId=4ce22e83-ca6b-47d0-9f69-02dc1024ef02@mydomain1.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56350 [17/Jun/2024:17:35:23.341] fe_ex2019~ be_ex2019_mapi/exch01 0/0/1/11/12 401 514 - - ---- 47/47/40/40/0 0/0 "POST /mapi/nspi/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56353 [17/Jun/2024:17:35:23.345] fe_ex2019~ be_ex2019_mapi/exch01 0/0/7/13/20 401 514 - - ---- 47/47/40/40/0 0/0 "POST /mapi/nspi/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56356 [17/Jun/2024:17:35:23.325] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/39/40 200 1139 - - ---- 47/47/39/39/0 0/0 "POST /mapi/nspi/?MailboxId=4ce22e83-ca6b-47d0-9f69-02dc1024ef02@mydomain1.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56350 [17/Jun/2024:17:35:23.355] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/31/32 200 1140 - - ---- 48/48/39/39/0 0/0 "POST /mapi/nspi/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56353 [17/Jun/2024:17:35:23.367] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/33/33 200 1139 - - ---- 48/48/38/38/0 0/0 "POST /mapi/nspi/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56350 [17/Jun/2024:17:35:23.355] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/31/32 200 1140 - - ---- 48/48/39/39/0 0/0 "POST /mapi/nspi/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:35:23 localhost haproxy[671]: 192.168.21.72:56353 [17/Jun/2024:17:35:23.367] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/33/33 200 1139 - - ---- 48/48/38/38/0 0/0 "POST /mapi/nspi/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:36:07 localhost haproxy[671]: 192.168.21.72:55287 [17/Jun/2024:17:15:08.795] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/36/1259090 200 1679 - - ---- 44/44/36/36/0 0/0 "POST /mapi/emsmdb/?MailboxId=4ce22e83-ca6b-47d0-9f69-02dc1024ef02@mydomain1.com HTTP/1.1"
Jun 17 17:36:07 localhost haproxy[671]: 192.168.21.72:55791 [17/Jun/2024:17:26:08.827] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/17/599058 200 1354 - - ---- 44/44/34/34/0 0/0 "POST /mapi/emsmdb/?MailboxId=4983ec4f-5055-4ee4-b075-99d505efe435@mydomain2.com HTTP/1.1"
Jun 17 17:36:07 localhost haproxy[671]: 192.168.21.72:55933 [17/Jun/2024:17:30:08.880] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/15/359005 200 1227 - - ---- 44/44/32/32/0 0/0 "POST /mapi/emsmdb/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:36:08 localhost haproxy[671]: 192.168.21.72:56380 [17/Jun/2024:17:36:08.938] fe_ex2019~ be_ex2019_mapi/exch01 0/0/3/9/12 401 514 - - ---- 43/43/36/36/0 0/0 "POST /mapi/emsmdb/?MailboxId=9e62a900-a795-4204-972f-6d0ee1cdc563@mydomain2.com HTTP/1.1"
Jun 17 17:36:08 localhost haproxy[671]: 192.168.21.72:56379 [17/Jun/2024:17:36:08.938] fe_ex2019~ be_ex2019_mapi/exch01 0/0/3/10/13 401 514 - - ---- 43/43/35/35/0 0/0 "POST /mapi/emsmdb/?MailboxId=4ce22e83-ca6b-47d0-9f69-02dc1024ef02@mydomain1.com HTTP/1.1"
Jun 17 17:36:08 localhost haproxy[671]: 192.168.21.72:56378 [17/Jun/2024:17:36:08.938] fe_ex2019~ be_ex2019_mapi/exch01 0/0/3/10/13 401 514 - - ---- 43/43/34/34/0 0/0 "POST /mapi/emsmdb/?MailboxId=4983ec4f-5055-4ee4-b075-99d505efe435@mydomain2.com HTTP/1.1"
Jun 17 17:37:04 localhost haproxy[671]: 192.168.21.72:56483 [17/Jun/2024:17:37:04.400] fe_ex2019~ be_ex2019_default/exch01 0/0/2/1/3 302 255 - - ---- 46/46/0/0/0 0/0 "GET / HTTP/1.1"
Jun 17 17:37:04 localhost haproxy[671]: 192.168.21.72:56483 [17/Jun/2024:17:37:04.407] fe_ex2019~ be_ex2019_owa/exch01 0/0/1/12/13 302 570 - - --NI 46/46/0/0/0 0/0 "GET /owa/ HTTP/1.1"
Jun 17 17:37:04 localhost haproxy[671]: 192.168.21.72:56483 [17/Jun/2024:17:37:04.424] fe_ex2019~ be_ex2019_owa/exch01 0/0/0/11/11 200 29349 - - --NI 46/46/0/0/0 0/0 "GET /owa/auth/logon.aspx?url=https%3a%2f%2fmymailserver.com%2fowa%2f&reason=0 HTTP/1.1"
Jun 17 17:37:04 localhost haproxy[671]: 192.168.21.72:56483 [17/Jun/2024:17:37:04.496] fe_ex2019~ be_ex2019_owa/exch01 0/0/0/14/14 200 61294 - - --NI 46/46/0/0/0 0/0 "GET /owa/auth/logon.aspx?replaceCurrent=1&url=https%3a%2f%2fmymailserver.com%2fowa%2f HTTP/1.1"
Jun 17 17:37:04 localhost haproxy[671]: 192.168.21.72:56483 [17/Jun/2024:17:37:04.612] fe_ex2019~ be_ex2019_owa/exch01 0/0/0/11/11 200 57089 - - --NI 46/46/0/0/0 0/0 "GET /owa/auth/15.2.986/themes/resources/segoeui-regular.ttf HTTP/1.1"
Jun 17 17:37:04 localhost haproxy[671]: 192.168.21.72:56483 [17/Jun/2024:17:37:04.652] fe_ex2019~ be_ex2019_owa/exch01 0/0/0/11/11 200 8201 - - --NI 46/46/0/0/0 0/0 "GET /owa/auth/15.2.986/themes/resources/favicon.ico HTTP/1.1"
Jun 17 17:37:42 localhost haproxy[671]: 192.168.21.72:56498 [17/Jun/2024:17:37:42.377] fe_ex2019~ be_ex2019_mapi/exch01 0/0/1/10/11 401 514 - - ---- 45/45/38/38/0 0/0 "POST /mapi/nspi/?MailboxId=4ce22e83-ca6b-47d0-9f69-02dc1024ef02@mydomain1.com HTTP/1.1"
Jun 17 17:37:42 localhost haproxy[671]: 192.168.21.72:56498 [17/Jun/2024:17:37:42.390] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/31/31 200 1140 - - ---- 45/45/38/38/0 0/0 "POST /mapi/nspi/?MailboxId=4ce22e83-ca6b-47d0-9f69-02dc1024ef02@mydomain1.com HTTP/1.1"

Does that mean anything?
Or could you please tell me how can i receive more informational logs?

This time the [ERR_CONNECTION_REFUSED] appears in Chrome when i tried to open OWA. And i opened Edge alongside and there are no problems on OWA page. WTH?

I noticed in logs that each connection starts with 401 response, if it may be a problem?
/mapi/nspi/?MailboxId=5c5de78e-6f85-4217-808f-3b61c3d4337e@mydomain1.com HTTP/1.1"
Jun 24 09:25:20 localhost haproxy[680]: 192.168.21.53:53008 [24/Jun/2024:09:25:20.656] fe_ex2019~ be_ex2019_mapi/exch01 0/0/0/37/37 200 1232 - - ---- 40/40/29/29/0 0/0 “POST /mapi/nspi/?MailboxId=5c5de78e-6f85-4217-808f-3b61c3d4337e@mydomain1.com HTTP/1.1”

Finally got it. My misconfig. I have setuped 2 DNS servers one internal and one external. When i deleted external DNS, everything got ok.