I've installed a SQL2012Express and ASG2015-P2 on a new 2012R2 server.
I started the ASG App as Administrator and created a new Database.
I checked the box set environment for all users but this doesn't happen.
When I try to open ASG as normal User there is no environment configured and I can not connect to the existing one.
That seems to be a SQL permissions problem - I think you try to use "Integrated" for your SQL connection - then you have to ensure that your windows users have access to the database - check Security of your SQL instance and check if your domain users are granted for the DB
Try first to set db_owner for your ASGRD database to ensure that this is the right problem :-)
Users need "Connect" and "Execute" - that should work
In MSSQL Management Studio => Security => Logins - click on your user or add one (you can also add Domain groups) - then goto "User mapping" - public is nneded for accessing the db, db_owner for testing - afterwards you can disable "db_owner" and goto your SQL instance => Properties => Permissions - there you can select your db and add Connect and Execute