the following workaround can help:
* edit the file /etc/httpd/conf.d/ovirt-engine-grafana-proxy.conf
* add "ProxyPreserveHost on" in Location /ovirt-engine-grafana
* restart the httpd service
~~~text (/etc/httpd/conf.d/ovirt-engine-grafana-proxy.conf)
<IfModule !mod_proxy>
LoadModule proxy_module modules/mod_proxy.so
</IfModule>
<Location /ovirt-engine-grafana>
ProxyPreserveHost on
ProxyPass
http://127.0.0.1:3000 retry=0 disablereuse=On
ProxyPassReverse
http://127.0.0.1:3000/ovirt-engine-grafana
</Location>
~~~