Invalid HELO name

I am trying out axigen on a linode server. I thought I had configured everything (including reverse DNS) and using my desktop Apple mail client I can send and receive an email from my new account on this axigen server to gmail and back.
However, when I try to send an email anywhere else, Apple mail pops up the following message

What step am I missing to make this work properly?

Thanks

Hello,

Please set log level to Protocol Communication for SMTP-Incoming, Processing and SMTP-Outgoing services and send us the logs (usually saved in everything.txt or default.txt files from log directory present into the Axigen working directory) after you have tried again to send the message to other external account than Gmail.

BR,
Ioan

I had already done that and noted that the problem was that the server was trying to connect to other mail servers using

 EHLO localhost

which of course is bogus.

The thing is, I had set the proper server name (see image, actual names pixelated out) and saved the configuration but that didn’t seem to help…until…

I reboot the linux server and now it works fine. (Yes, I know, I probably could have just restarted the axigen server). But surely, if a restart is required after changing the server name, the “Save configuration” should have done that restart, or at least prompted me to restart.

Edit: Forgot to post image

screenshot_4107