Can access Admin, but not tenants

Ubuntu 18.04.3 LTS
Tomcat/8.5.23 behind an Apache with https://
Razuna 1.9.6

I had to remove all https:// in the links mentioned below, because as a new User, I am not allowed
to enter that many links in a post.

Hi there! My problem is I can access the admin page with MY-DOMAIN.COM/razuna/admin/

If I try to access one of the tenants, for example MY-DOMAIN.COM/razuna/raz2/dam
I make it to the Login Page, but after entering my credentials, the server returns this: localhost:8080/razuna/raz2/dam/index.cfm and I see nothing.

What puzzels me is when I am on the Admin page and move my mouse over the links on the left side (General Configuration, Plugins, Users, etc.) I see the correct URL down in the Browser.

but only when I move my mouse over the Flush admin cache link, I get this:

Does anybody know where I went wrong in the configuration?
Your help is really appreciated!
Thanks, Lars

Solved it by my self by adding the following lines to the 000-default.conf AND the 000-default-le-ssl.conf files.

ProxyPreserveHost On

ProxyPass / http://localhost:8080/
ProxyPassReverse / http://localhost:8080/

Maybe it helps somebody who runs into the same problem.

Best regards, Lars