Good day,
Description: Service cannot be started. System.Data.SqlClient.SqlException (0x80131904): Login failed for user...
I was initially using Windows authentication, before I changed to SQL Server authentication, both worked in Visual Studio but after deployment as a service on my local Windows 10 system, it fails.
Note: It is recommended in most cases to use Windows Authentication if this is supported.
More information that could help
- is your SQL Server installed in the same machine as the service (the application that connect the server)?
- what is your connection string (remove the sensitive information like password)
- As other already asked, we need to get the exact full information from the error log file
In the mean time let's play with some guessing, please check if this help you
- Make sure that SQL Server is configured to use Mixed mode
- Since you are using SQL Authentication now, in the connection string set: Integrated Security=False