RDS Connection Broker with High Availability

Hello,

I installed RDS on my servers windows server 2012 R2. My database is installed on a windows server 2008 R2.

The firewall is disabled. I created a SQL account with db_creator rights. I created a DNS round robbin.

Below broker settings:

Database connection string :
DRIVER=SQL Server Native Client 11.0;SERVER=ax-bi-sql;Trusted_Connection=Yes;APP=Remote Desktop Services Connection Broker;Database=RDSBrokers

Folder to store database file :
E:\SQL2014

DNS round robin name:
rds.mondomain.local

But I get an error :

I do not know why. Please could you help me ?