The server principal "" is not able to access the database "DatabaseName" under the current security context.

Error:  The server principal "" is not able to access the database "DatabaseName" under the current security context.

for conection string: "Data Source=.'';Initial Catalog=DatabaseName ;User Id=IncidentManagement ;Password=wuwaye6U5+uz;" providerName="System.Data.SqlClient"

Fix: This error you receive when the service account using from .net application doesn’t have sufficient permissions to access the database. Very simple to fix. Go to the login properties and see whether this account has access to the database or not and grant it.