MartinDDD
Push mail still works – but you need a server that will accept requests from the HDR client.
What has happened is that email service providers have been turning off the unsecured and less secure protocols and ports on their servers over the last few years.
If your mail provider has done this, push mail is unable to send the mails as it doesn’t have the more secure options.
What is your setting for “Outgoing mail (SMTP) server and port” ?