A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 - The certificate chain was issued by an authority that is not trusted.)

 Original answer:

You likely don't have a CA signed certificate installed in your SQL VM's trusted root store.

If you have Encrypt=True in the connection string, either set that to off (not recommended), or add the following in the connection string (also not recommended):

TrustServerCertificate=True

SQL Server will create a self-signed certificate if you don't install one for it to use, but it won't be trusted by the caller since it's not CA-signed, unless you tell the connection string to trust any server cert by default.

Changed in appsettings.json file:

{

  "Logging": {

    "LogLevel": {

      "Default": "Information",

      "Microsoft.AspNetCore": "Warning"

    }

  },

  "ConnectionStrings": {

    "DefaultConnection": "Server=WKWIN9498383; Database=dbGridCustom;TrustServerCertificate=True; Trusted_Connection=True; MultipleActiveResultSets=true"

  },

  "AllowedHosts": "*"

}