How to access to database in worker service when published as windows service?

I've created worker service on .net core 3.1. I published it to folder and using powershell registered new windows service.

When I start service it should connect to database and get records from db.

It throws

Microsoft.Data.SqlClient.SqlException (0x80131904): Cannot open database "exmapleDB" requested by the login. The login failed. Login failed for user 'NT AUTHORITY\SYSTEM'.

Any suggestions?