I try to connect from webpart to database server. Error happen in the line:
conn.Open()
Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.
Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.
I'm using Sharepoint 2013 version.