Sharepoint connection fails (Winforms, VB.Net) - vb.net

Question

I did a small development where it is necessary to connect to a SharePoint list, the development works well with my user, but when testing with another user who has the same privileges on the site, it sends the following error message
"The sign-in name or password does not match one in the Microsoft Account System. "
I already tried with other users that the site are owners, but I get the same result.
Can you help me see what is the error in the above?
This is my code.
Imports Microsoft.SharePoint.Client
Imports Microsoft.SharePoint
Imports System.Security
Imports System.Net
Public Class Form4
Dim siteUrl As String = "https://example.sharepoint.com/site/SiteExample/"
Dim context As New ClientContext(siteUrl)
Dim web As Web
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Dim userNameSP As String = TextBox1.Text
Dim password As String = TextBox2.Text
Dim secureString As SecureString = New NetworkCredential("", password).SecurePassword
Dim cred = New SharePointOnlineCredentials(userNameSP, secureString)
Dim clientContext As New ClientContext(siteUrl)
clientContext.Credentials = cred
Dim web As Web = clientContext.Web
Dim oWebsite As Web = clientContext.Web
Dim collList As ListCollection = oWebsite.Lists
Dim oList As List = collList.GetByTitle("Example Test")
clientContext.Load(oList)
clientContext.ExecuteQuery()
Dim query As CamlQuery = CamlQuery.CreateAllItemsQuery()
query.ViewXml = "<View Scope='RecursiveAll'><Query><ViewFields><FieldRef Name='Category/></ViewFields></Query></View>"
Dim AllItems As ListItemCollection = oList.GetItems(query)
clientContext.Load(AllItems)
clientContext.ExecuteQuery()
If AllItems.Count > 0 Then
... Do Something
end if
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
End Class
Thank you in advance.

Answer 1

Did the user account enable MFA Authentication ?
I tested the same code snippet with a normal user account without MFA, it's working as expected.
Please check MFA Status in this:
https://account.activedirectory.windowsazure.com/UserManagement/MultifactorVerification.aspx?BrandContextID=O365
If enabling the MFA, please disable it, as CSOM didn't support MFA currently.

Answer 2

This is the solution code to do log-in in a sharepoint.
Imports Microsoft.Office.Interop
Imports System.IO
Imports Microsoft.SharePoint.Client
Imports Microsoft.SharePoint
Imports System.Security
Imports System.Net
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim siteUrl As String = "https://example.sharepoint.com/sites/TRAINING/"
Dim authManager = New OfficeDevPnP.Core.AuthenticationManager()
Dim ctx As ClientContext = authManager.GetWebLoginClientContext(siteUrl)
Dim web As Web = ctx.Web
ctx.Load(web, Function(w) w.Title)
ctx.ExecuteQuery()
Console.WriteLine("You have connected to {0} site, with Multi Factor Authentication enabled!!", web.Title)
Try
Do Something...
Catch ex As Exception
MessageBox.Show("An error occurred:" & Environment.NewLine & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End Sub
Sorry for the delay.
Regards.