MySQL 8.0.30 - Error "connection must be valid and open" - mysql

Question

I have .NET application which connects mysql database at backend. Following is my code and MySQL connection string use for development.
Code:
Imports MySql.Data.MySqlClient
Module SQLConn
' Global variables declaration
Public ServerMySQL As String
Public PortMySQL As String
Public UserNameMySQL As String
Public PwdMySQL As String
Public DBNameMySQL As String
Public conn As New MySqlConnection
Public sqL As String
'/ Connection DB Public Module
'/ -------------------------------------------------
Public Sub ConnDB()
conn.Close()
getData()
Try
conn.ConnectionString = "Server = '" & ServerMySQL & "'; " _
& "Port = '" & PortMySQL & "'; " _
& "Database = '" & DBNameMySQL & "'; " _
& "uid = '" & UserNameMySQL & "'; " _
& "pwd = '" & PwdMySQL & "'"
conn.Open()
Catch ex As Exception
MsgBox("The system failed to establish a connection", MsgBoxStyle.Information, "Database Settings")
End Try
End Sub
' / Load Application Settings
' / -------------------------------------------------
Sub getData()
Dim AppName As String = Application.ProductName
Try
DBNameMySQL = GetSetting(AppName, "DBSection", "DB_Name", "ax_db")
ServerMySQL = GetSetting(AppName, "DBSection", "DB_IP", "localhost")
PortMySQL = GetSetting(AppName, "DBSection", "DB_Port", "3306")
UserNameMySQL = GetSetting(AppName, "DBSection", "DB_User", "root")
PwdMySQL = GetSetting(AppName, "DBSection", "DB_Password", "xxxxx")
Catch ex As Exception
MsgBox("System registry was not established, you can set/save " &
"these settings by pressing F1", MsgBoxStyle.Information)
End Try
End Sub
This is working pretty fine with early MySQL Community Versions 5.5.3 or similar. Application was running perfectly fine. I want to upgrade MySQL to include more multi-lingual features to my app. I have upgraded to MySQL Community version 8.0.30 and server is running
it gives me an error "connection must be valid and opened".
I tried simple connection string ("server=localhost;uid=root;pwd=xxxxx;database=ax_db") and some other suggestions made in other posts here in www.stackoverflow.com as ("server=localhost;port=3306;user id=roote;pwd=xxxxx;database=ax_db").
Tried even by adding "Persist Security Info=False; Convert Zero Datetime=True" to the connection string. but no luck. app keeps on throws same error.
Here is my Developer Environment
MySQL Connector/NET installed
Windows 10
.NET Framework 4.7.2
Visual Studio 2019
MySQL Community Server 8.0.30
MySQL Workbench 8