Help with setting up Nextcloud on Raspberry Pi 4

Hello,
I tried to set up Nextcloud on my Raspberry Pi 4. Everything went well till I wanted to go to the blue login screen. There it says “NextCloudPi not yet initialized, trying again in a few seconds …”
Does anyone know what the problem is?

NextCloudPi diagnostics

cat: /usr/local/etc/ncp-version: Datei oder Verzeichnis nicht gefunden
NextCloudPi version
distribution         Raspbian GNU/Linux 10 \n \l
automount            no
USB devices          sda 
datadir               (doesn't exist)
rootfs usage         7,5G/27G
swapfile             /var/swap
dbdir                /var/lib/mysql
Nextcloud check      ok
Nextcloud version    17.0.2.1
HTTPD service        up
PHP service          up
MariaDB service      up
Redis service        up
Postfix service      up
internet check       ok
port check 80        closed
port check 443       closed
IP                   ***REMOVED SENSITIVE VALUE***
gateway              ***REMOVED SENSITIVE VALUE***
interface            wlan0
certificates         ***REMOVED SENSITIVE VALUE***
NAT loopback         no
uptime               23min

Nextcloud configuration

Nextcloud is not installed - only a limited number of commands are available

                                                            
  There are no commands defined in the "config" namespace.  
                                                            


HTTPd logs

[Thu Jan 30 18:37:36.513522 2020] [authz_host:error] [pid 23652:tid 2873304096] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /activate/ failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.513787 2020] [authz_host:error] [pid 23652:tid 2873304096] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /activate/index.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.642574 2020] [authz_host:error] [pid 23652:tid 2873304096] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /activate/CSS.css failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.678070 2020] [authz_host:error] [pid 23652:tid 2873304096] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /js/minified.js failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.686099 2020] [authz_host:error] [pid 23652:tid 2764174368] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /img/ncp-logo.svg failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.693074 2020] [authz_host:error] [pid 23652:tid 2881696800] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /img/clippy.svg failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.693837 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /img/loading-small.gif failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.694555 2020] [authz_host:error] [pid 23652:tid 2890089504] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /activate/JS.js failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:36.725193 2020] [authz_host:error] [pid 23652:tid 2890089504] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /img/background.png failed, reason: unable to get the remote host name, referer: https://192.168.2.113/activate/CSS.css
[Thu Jan 30 18:37:36.755813 2020] [authz_host:error] [pid 23652:tid 2890089504] [client 192.168.2.113:47962] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:49.052761 2020] [authz_host:error] [pid 23652:tid 2890089504] [client 192.168.2.113:47970] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:49.789575 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:47970] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:37:59.898271 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:47978] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:38:01.783779 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:47978] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:38:11.780654 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:47988] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:38:14.745018 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:47988] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:38:25.766223 2020] [authz_host:error] [pid 23653:tid 2780976160] [client 192.168.2.113:47996] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:38:37.792691 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:48006] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:38:49.764176 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:48014] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name
[Thu Jan 30 18:39:01.796516 2020] [authz_host:error] [pid 23652:tid 2898482208] [client 192.168.2.113:48022] AH01753: access check of 'localhost' to /ncp-launcher.php failed, reason: unable to get the remote host name

Database logs

2020-01-30 17:40:13 0 [Note] InnoDB: Uses event mutexes
2020-01-30 17:40:13 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
2020-01-30 17:40:13 0 [Note] InnoDB: Number of pools: 1
2020-01-30 17:40:13 0 [Note] InnoDB: Using generic crc32 instructions
2020-01-30 17:40:13 0 [Note] InnoDB: Initializing buffer pool, total size = 1.625G, instances = 1, chunk size = 128M
2020-01-30 17:40:13 0 [Note] InnoDB: Completed initialization of buffer pool
2020-01-30 17:40:13 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2020-01-30 17:40:14 0 [Note] InnoDB: 128 out of 128 rollback segments are active.
2020-01-30 17:40:14 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2020-01-30 17:40:14 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2020-01-30 17:40:14 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2020-01-30 17:40:14 0 [Note] InnoDB: 10.3.17 started; log sequence number 6991472; transaction id 5124
2020-01-30 17:40:14 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2020-01-30 17:40:14 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-01-30 17:40:14 0 [Note] Server socket created on IP: '127.0.0.1'.
2020-01-30 17:40:14 0 [Note] InnoDB: Buffer pool(s) load completed at 200130 17:40:14
2020-01-30 17:40:14 0 [Note] Reading of all Master_info entries succeeded
2020-01-30 17:40:14 0 [Note] Added new Master_info '' to hash table
2020-01-30 17:40:14 0 [Note] /usr/sbin/mysqld: ready for connections.
Version: '10.3.17-MariaDB-0+deb10u1'  socket: '/run/mysqld/mysqld.sock'  port: 3306  Raspbian 10

Nextcloud logs

tail: '/nextcloud.log' kann nicht zum Lesen geöffnet werden: Datei oder Verzeichnis nicht gefunden