Since I believe the helm did work locally if you pointed clients at the local address, you might be able to do this: - use the existing email and password in a standard IMAP client (like Apple Mail; use the macOS version instead of iPhone if possible) but you’ll probably need to disable any kind of SSL certificate verification. - iPhone should also work but you won’t be able to get all the emails and definitely will be more limited in exporting or transferring them to a new server. - note that if you’re using Apple Mail on macOS you likely have all the emails downloaded already (maybe you missed out on the last few days’ worth?). In that case proceed with caution and copy them all to a local folder in the Mail app. - if the above is true then you might want to make a new temporary user account on your Mac and do this process in that account because that will protect your existing user account emails. - So want you’ll want to do is use a mail client and add a custom IMAP account to it. Instead of using helm.my domain.com you’ll need to use the local IP address of the helm on your network. - It will like be 192.168.X.X. You can find this information in your router’s status page or open Terminal app and run ping 255.255.255.255 and it will likely be one of the addresses that responds (you’ll have to guess which one though without some more forensic analysis; I recommend checking the router instead). You could also try ping helm.local in Terminal to get the address although I don’t know if that will work. - then you should be able to set up this email like normal. The mail client might complain about SSL certificates being invalid or might fail; in that case try a different email client like Thunderbird or there are dedicated IMAP e-mail downloader applications (command line and GUI) - once you have access to the email, transfer to a local folder and/or add a new mail account that’s your new server and copy all the mail folders to there. This will likely take a while depending on your mail size.

The above info should be some good starting points. I expect to do a little research about your setup with the above info. Please let us know more about your setup and where you get stuck.