Web Interface not reachable, pi-hole itself is working

Output for pihole -r

pihole -r

  [✓] Root user check

        .;;,.
        .ccccc:,.
         :cccclll:.      ..,,
          :ccccclll.   ;ooodc
           'ccll:;ll .oooodc
             .;cll.;;looo:.
                 .. ','.
                .',,,,,,'.
              .',,,,,,,,,,.
            .',,,,,,,,,,,,....
          ....''',,,,,,,'.......
        .........  ....  .........
        ..........      ..........
        ..........      ..........
        .........  ....  .........
          ........,,,,,,,'......
            ....',,,,,,,,,,,,.
               .',,,,,,,,,'.
                .',,,,,,'.
                  ..'''.

  [✓] Update local cache of available packages
  [i] Existing PHP installation detected : PHP version 7.3.19-1~deb10u1
  [i] Repair option selected

  [✓] Checking apt-get for upgraded packages... 40 updates available
  [i] It is recommended to update your OS after installing the Pi-hole!

  [i] Installer Dependency checks...
  [✓] Checking for dhcpcd5
  [✓] Checking for git
  [✓] Checking for iproute2
  [✓] Checking for whiptail
  [✓] Checking for dnsutils

  [✓] Supported OS detected
  [i] SELinux not detected
  [i] Performing reconfiguration, skipping download of local repos
  [✓] Resetting repository within /etc/.pihole...
  [✓] Resetting repository within /var/www/html/admin...
  [i] Main Dependency checks...
  [✓] Checking for cron
  [✓] Checking for curl
  [✓] Checking for iputils-ping
  [✓] Checking for lsof
  [✓] Checking for netcat
  [✓] Checking for psmisc
  [✓] Checking for sudo
  [✓] Checking for unzip
  [✓] Checking for wget
  [✓] Checking for idn2
  [✓] Checking for sqlite3
  [✓] Checking for libcap2-bin
  [✓] Checking for dns-root-data
  [✓] Checking for libcap2
  [i] Checking for lighttpd (will be installed)
  [✓] Checking for php7.3-common
  [✓] Checking for php7.3-cgi
  [✓] Checking for php7.3-sqlite3
  [✓] Checking for php7.3-xml
  [✓] Checking for php7.3-json
  [✓] Checking for php7.3-intl
  [i] Processing apt-get install(s) for: lighttpd, please wait...
-------------------------------------------------------------------------------
Vormals nicht ausgewähltes Paket lighttpd wird gewählt.
(Lese Datenbank ... 127195 Dateien und Verzeichnisse sind derzeit installiert.)
Vorbereitung zum Entpacken von .../lighttpd_1.4.53-4+deb10u1_armhf.deb ...
Entpacken von lighttpd (1.4.53-4+deb10u1) ...
lighttpd (1.4.53-4+deb10u1) wird eingerichtet ...
Created symlink /etc/systemd/system/multi-user.target.wants/lighttpd.service → /lib/systemd/system/lighttpd.service.
Trigger für man-db (2.8.5-2) werden verarbeitet ...
Trigger für systemd (241-7~deb10u4+rpi1) werden verarbeitet ...
-------------------------------------------------------------------------------
  [✓] Enabling lighttpd service to start on reboot...
  [✓] Checking for user 'pihole'

  [i] FTL Checks...

  [✓] Detected ARMv7 processor (with hard-float support)
  [i] Checking for existing FTL binary...
  [i] Latest FTL Binary already installed (v5.3.2). Confirming Checksum...
  [i] Checksum correct. No need to download!
  [✓] Installing scripts from /etc/.pihole

  [i] Installing configs from /etc/.pihole...
  [i] Existing dnsmasq.conf found... it is not a Pi-hole file, leaving alone!
  [✓] Copying 01-pihole.conf to /etc/dnsmasq.d/01-pihole.conf

  [i] Installing blocking page...
  [✓] Creating directory for blocking page, and copying files
  [i] Backing up index.lighttpd.html
      No default index.lighttpd.html file found... not backing up

  [✓] Installing sudoer file

  [✓] Installing latest Cron script

  [✓] Installing latest logrotate script
  [i] Backing up /etc/dnsmasq.conf to /etc/dnsmasq.conf.old
  [✓] man pages installed and database updated
  [i] Testing if systemd-resolved is enabled
  [i] Systemd-resolved is not enabled
  [✓] Restarting lighttpd service...
  [✓] Enabling lighttpd service to start on reboot...
  [i] Restarting services...
  [✓] Enabling pihole-FTL service to start on reboot...
  [✓] Restarting pihole-FTL service...
  [✓] Deleting existing list cache
  [i] Neutrino emissions detected...
  [✓] Pulling blocklist source list into range

  [✓] Preparing new gravity database
  [i] Using libz compression

  [i] Target: https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts
  [✓] Status: Retrieval successful
  [i] Received 58230 domains

  [i] Target: https://mirror1.malwaredomains.com/files/justdomains
  [✓] Status: Retrieval successful
  [i] Received 26854 domains

  [✓] Storing downloaded domains in new gravity database
  [✓] Building tree
  [✓] Swapping databases
  [i] Number of gravity domains: 85084 (85053 unique domains)
  [i] Number of exact blacklisted domains: 3
  [i] Number of regex blacklist filters: 1
  [i] Number of exact whitelisted domains: 1
  [i] Number of regex whitelist filters: 0
  [✓] Flushing DNS cache
  [✓] Cleaning up stray matter

  [✓] DNS service is listening
     [✓] UDP (IPv4)
     [✓] TCP (IPv4)
     [✓] UDP (IPv6)
     [✓] TCP (IPv6)

  [✓] Pi-hole blocking is enabled

  [i] The install log is located at: /etc/pihole/install.log
Update Complete! 

  Current Pi-hole version is v5.2.1.
  Current AdminLTE version is v5.2.1.
  Current FTL version is v5.3.2.
pi@Pi-Hole:~ $