[Lam-public] Problem with the tree view

[<SHa...@t-...>]

Hello,

after I logged in the ldap-account-manager and i click left to the base dn 
nothing happens. The circle to the left side of the base dn turns and 
turns. After 5 minutes I get the following error message "There was a 
problem with the request". My system is a Debian 6.5 with php 7.3. Here is 
my Apache2 configuration of ldap-account-manager

cat /etc/apache2/sites-available/lam.conf
...
<VirtualHost lam.intern.harnet.de:80>
ServerName lam.intern.harnet.de:80
DocumentRoot "/var/www/html/ldap-account-manager"
RedirectMatch permanent ^(.*)$ https://lam.intern.harnet.de
</VirtualHost>
<VirtualHost lam.intern.harnet.de:443>
ServerName lam.intern.harnet.de:443
DocumentRoot "/var/www/html/ldap-account-manager/"
ServerAdmin web...@ha...
SSLEngine on
SSLCertificateFile /etc/openxpki/ssl/ca-one/lam.intern.harnet.de.crt
SSLCertificateKeyFile /etc/openxpki/ssl/ca-one/lam.intern.harnet.de.key
ErrorLog /var/log/apache2/apache-lam-error.log
TransferLog /var/log/apache2/apache-lam-access.log
CustomLog /var/log/apache2/apache-lam-request.log combined

<Directory /var/www/html/ldap-account-manager/>
Options +FollowSymLinks
AllowOverride All
Require all granted
DirectoryIndex index.html
</Directory>
<Directory /var/lib/ldap-account-manager/tmp>
Options -Indexes
</Directory>
<Directory /var/lib/ldap-account-manager/tmp/internal>
Options -Indexes
Require all denied
</Directory>
<Directory /var/lib/ldap-account-manager/sess>
Options -Indexes
Require all denied
</Directory>
<Directory /var/lib/ldap-account-manager/config>
Options -Indexes
Require all denied
</Directory>
<Directory /var/www/html/ldap-account-manager/lib>
Options -Indexes
Require all denied
</Directory>
<Directory /var/www/html/ldap-account-manager/help>
Options -Indexes
Require all denied
</Directory>
<Directory /var/www/html/ldap-account-manager/locale>
Options -Indexes
Require all denied
</Directory>
</VirtualHost>
...
 
Why can not I see the bottom structures on the left side of the dashboard?
 
Greetings from Stefan Harbich