Enable Cookies for reverse Proxy and Apache2 - web

Question

i try to access an application on a tomcat server via a reverse proxy and apache2.
The reverse proxy is working just fine, but the application throws an error, that cookies are disabled.
I googled but nothing helped.
My vhost.conf file:
<VirtualHost *:80>
ServerName testcms.mydomain.de
ServerAdmin webmaster#localhost
DocumentRoot /var/www/cms
ProxyPreserveHost On
ProxyPass / http://127.0.0.1:8080/opencms/
ProxyPassReverse / http://127.0.0.1:8080/opencms/
ProxyPassReverseCookieDomain http://localhost:8080/opencms testcms.mydomain.de
ProxyPassReverseCookiePath / /cms/Cookies
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
RewriteEngine on
RewriteCond %{SERVER_NAME} =testcms.mydomain.de
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>
<IfModule mod_ssl.c>
<VirtualHost *:443>
ServerName testcms.mydomain.de
ServerAdmin webmaster#localhost
DocumentRoot /var/www/cms
ProxyPreserveHost On
ProxyPass / http://127.0.0.1:8080/opencms/
ProxyPassReverse / http://127.0.0.1:8080/opencms/
ProxyPassReverseCookieDomain 127.0.0.1:8080/opencms/ testcms.mydomain.de
ProxyPassReverseCookiePath / /cms/cookies
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
SSLEngine on
SSLCertificateFile /etc/letsencrypt/live/testcms.mydomain.de/fullchain.pem
SSLCertificateKeyFile /etc/letsencrypt/live/testcms.mydomain.de/privkey.pem
Include /etc/letsencrypt/options-ssl-apache.conf
</VirtualHost>
</IfModule>
The ProxyPassReverseCookieDomain and ProxyPassReverseCookiePath should help, but they dont.
Did I miss something while implementing the reverse proxy?
Thanks for the help!