If your listserv server is at (at least) level 2014a, the "DMARC" issue is removed and you can freely have subscribers and posters from any domain. Unique Listserv technology does the heavy lifting.

Some other mailing list server software has addressed this issue, but none like or as well as Listserv.

Search "dmarc" for more complete descriptions of the problem, but the short explanation is ...

If certain domains see email arrive from one of their users, say yahoo.com, but was sent from a different domain, say your Listserv server, the mail will be rejected, and in a fashion that some mail systems will consider the rejection to be a serious and permanent error with repercussions to your site, your list and some of your subscribers.

On Sep 4, 2015 9:57 AM, "Crovo, Bob" <[log in to unmask]> wrote:

Was this maybe covered before?

https://help.yahoo.com/kb/SLN7253.html?impressions=true describes why my emails to a ymail address bounced. The page includes this advice:

In almost all cases, we recommend you switch to sending mail from your own domain. For mailing lists, also known as "listservs," you should change your sending behavior by adding the mailing lists’ address to the "From:" line, rather than the sender’s address. Also, enter the actual user/sender address into the "Reply-To:" line.

You can also change your email client's "send as" settings to use Yahoo SMTP servers. Consult with your third-party email client's help pages, or FAQs, for information on how to change these settings.

And here’s the error that was generated by the attempt by Listserv to send an email to a Ymail.com address.

It doesn’t sound as though the fix is within my power. Any advice?

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