System.Windows.Forms.pdb not loaded

[amnon]

Hello,
I've just started learning programming and I'm stuck creating a new instance of a class.
I created a simple library with a class and a constructor

Public Class Person
    sub main()
        MessageBox.Show("Message from class")
    EndSub
End Class

In the application, I added a library reference and imported it

Imports WinFormsLibrary1
Public Class Form1
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim MyNewInstance As New Person
    End Sub
End Class

when i run i get an error

System.Windows.Forms.pdb not loaded

I went through all the topics on the net, I found a few hints, such as: disabling Debugging option Enable.NET Framework source stepping and Enable Just My Code. In the Symbol File tab, I checked the Microsoft Symbol Servers option, but it didn't help. I will be grateful for any hint