I’m sorry, but I’m really not an expert on every ISP’s servers and every mail client on the planet. I have been using Apple products almost exclusively on this list since it was on the UMN server while I was running a Mac IIsi and System 7 with few of the issues that you all seem to have.  

If messages are being sorted into your spam folder, you’ll have to figure out what is doing it and why they’re seen as not legitimate email. Look at the headers and see what has tripped the switch. Is the message being quarantined by you mail client or by your ISP’s mail server? If by your mail client, search the Internet tubes for other folks that are having the same problem using the same client. If by the server, contact your ISP’s help folk and figure out how to whitelist mail from the listserv. 

You can set your subscription to append Vanagon to the subject of each and every post and whitelist 'Subject contains Vanagon.' Whitelisting @gerry.vanagon.com domain may help, as that’s where the mail comes THROUGH, but each message will show the sender’s address as where it’s from so to whitelist an address, you may have to list each individual sender’s address.

I’ll do what I can to help, but really, it’s in your hands.

Jim

Sent using Apple Mail 12.4 on a Mac Pro running 10.14.16 through a not gmail account.