Dear RedHat Community

I have installed Ansible Tower (ansible-tower-setup-3.5.0-1) on RHEL7 - the software is up and running. But when I want to add a license key, I get an error 400. Here is the content of my inventory file before the tower installation:

[tower]
localhost ansible_connection=local

[database]

[all:vars]
admin_password='mypasswordhere'

pg_host='srvrhtower'
pg_port='5433'

pg_database='ansible'
pg_username='ansible'
pg_password='mypasswordhere'

rabbitmq_username=tower
rabbitmq_password='mypasswordhere'
rabbitmq_cookie=cookiemonster

The host can be resolved by /etc/hosts
[root@srvrhtower ~]# cat /etc/hosts

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

192.168.59.142 srvrhtower srvrhtower.kestenholz.net

Can you tell my why this error 400 occurs? I Have attached the tower.log.

Regards, Martin