Sql-server – SQL Express Reporting Server 2014

I have a problem getting my SQL SSRS service working.
Version: SQL Express 2014

When I try to start SQL SSRS in services, the service starts, but looking at the event viewer it fails to connect to report server.

EVENT ID:107
Report Server Windows Service (SQLEXPRESS) cannot
connect to the report server database.

My understanding is that the service connects to the SSRS databases using the rsreportserver.config file. So in my head the fault must lie there.

I then checked whether I can connect to the reporting server database using the credentials specified in rsreportserver.config.

I created a .UDL file and successfully connected to the database using:

user: sa
pass: testing

I then decided to rewrite the configuration file using rsconfig utility.

-c -s SERVERNAME -i SQLEXPRESS -d ReportServer$SQLEXPRESS -a SQL -u sa -p testing -t

This works without any problems or errors.

Regardless the service continuously does not connect to the reporting database.

Also when I use the Reporting Services Configuration Manager – DATABASE connection details. I cannot successfully connect to the database using the same SA account and password. Nor can I actually create a new database within Reporting Services Configuration Manager using the sa account or the administrator account (both which can actually connect to the database using the UDL file).

Any help would be greatly appreciated.