Why can't redmine be opened from the web?

Question

Apache HTTP Server

In general, redmine is installed on a virtual machine on the local network and is available at help.domen.com, but if you try to access this domain from outside (hosts are available by specifying the domain.com:4000 port), the page in the browser simply loads and then reports that connection reset (408).
Static sites from the same server are available.

curl -I help.domain.com:4000
HTTP/1.1 302 Found
Date: Thu, 08 Mar 2018 20:02:22 GMT
Server: Apache/2.4.6 (CentOS) Phusion_Passenger/5.1.11
X-Runtime: 0.127567
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
X-Content-Type-Options: nosniff
X-Request-Id: b5461bce-86da-444e-b71d-e4dfce6137bb
X-Powered-By: Phusion Passenger 5.1.11
Location: http://help.domain.com:4000/login?back_url=http%3A%2F%2Fhelp.domain.com%3A4000%2F404
Transfer-Encoding: chunked
Status: 302 Found
Content-Type: text/html; charset=utf-8

In the host log:

[08/Mar/2018:22:47:15 +0300] "GET / HTTP/1.1" 302 156 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36"
[08/Mar/2018:22:47:15 +0300] "GET /login?back_url=http%3A%2F%2Fdomen.com%3A4000%2F404 HTTP/1.1" 200 13164 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36

The debug log level says nothing but:

[Thu Mar 08 22:43:32.023152 2018] [authz_core:debug] [pid 13216] mod_authz_core.c(809): [client ***:52212] AH01626: authorization result of Require all granted: granted
[Thu Mar 08 22:43:32.023159 2018] [authz_core:debug] [pid 13216] mod_authz_core.c(809): [client ***:52212] AH01626: authorization result of <RequireAny>: granted

Host config

<VirtualHost *:80>
        DocumentRoot /var/www/redmine/public
        ServerName help.domain.com
        ServerAlias www.help.domain.com

        <Directory /var/www/redmine/public>
                RailsBaseURI /
                PassengerResolveSymlinksInDocumentRoot on
                PassengerFriendlyErrorPages on
                Options -Indexes +FollowSymLinks +MultiViews
                AllowOverride all
                Require all granted
        </Directory>

        ErrorLog /var/log/httpd/redmine.error.log

        LogLevel error

        CustomLog /var/log/httpd/redmine.access.log combined
</VirtualHost>