The changes that you have made mean that you will now have to create a Mail app password for the email address concerned. I will post instructions at the end of this message. However, at the moment VM Mail is down and you will need to wait for it to be restored before creating the app password.
VM have recently changed the log in requirements for accessing VM Mail via third party apps.
If you change the password for the account in My Virgin Media > Account settings > Account details you will not be able to use the new password to access the account via an email client. Email client access now requires an app specific password which can be generated in the MyVM > Account Settings > Account details > Mailbox App password management