Reverse Proxy backend having Path

Thanks for fast reply!

Was comparing it directly on the backed and It should be without the /SOGo/ prefix:

No. SOGo wasnt altered in any way for this particular subdomain. It is part of mailcow dockerized stack. So mainly is accessible via mail.example.com/SOGo/ but I wanted here a separate subdomain just for the email client.

<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
      <head>
        <title sg-default="SOGo Groupware">SOGo Groupware</title>
        <meta name="hideFrame" content="0" />
        <meta name="description" content="SOGo Web Interface" />
        <meta name="author" content="Inverse inc." />
        <meta name="robots" content="stop" />
        <meta name="build" content="@shiva2.inverse 201903020208" />
        <meta name="viewport" content="width=device-width, initial-scale=1,maximum-scale=1" />
        <link rev="made" href="mailto:support@inverse.ca" />
        <link href="/SOGo.woa/WebServerResources/img/sogo.ico?lm=1551559708" rel="shortcut icon" type="image/x-icon" />
          <link href="/SOGo.woa/WebServerResources/css/theme-default.css" rel="stylesheet" type="text/css" />
        <link href="/SOGo.woa/WebServerResources/css/styles.css" rel="stylesheet" type="text/css" />

...omitted

          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/lodash.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-animate.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-sanitize.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-aria.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-cookies.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-messages.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-material.min.js"></script>
          <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/vendor/angular-ui-router.min.js"></script>
            <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/Main.js?lm=1551559708"></script>
            <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/Common.js?lm=1551559708"></script>
            <script type="text/javascript" src="/SOGo.woa/WebServerResources/js/custom-sogo.js?lm=1546011515"></script>
      </body>
    </html>

Thanks a lot! Michal