Messages bouncing again

I have been getting messages again from the ezmlm program. They have improved - at least now I shall only be ejected if the probe fails, not if *I* bounce another message. In itself it is not a problem, since I can ignore or delete them, but it means that I get none of deloptes' messages to this list. The error message that I am sent suggests that it is Gmail's fault, but both deloptes and I use exactly the same email addresses on the Debian list as on this one, and I get his messages there, so it must in some way be due to ezmlm. Is there anything I, or anyone here, can do about it? Lisi ------------------------------------------------------------------------------- <quote> Hi! This is the ezmlm program. I'm managing the trinity-users(a)lists.pearsoncomputing.net mailing list. I'm working for my owner, who can be reached at trinity-users-owner(a)lists.pearsoncomputing.net. Messages to you from the trinity-users mailing list seem to have been bouncing. I've attached a copy of the first bounce message I received. If this message bounces too, I will send you a probe. If the probe bounces, I will remove your address from the trinity-users mailing list, without further notice. Copies of these messages may be in the archive. [snip] Here are the message numbers: 9751 9753 9755 9759 9770 9771 9773 9775 9778 9780 9787 9802 9807 9815 9820 --- Enclosed is a copy of the bounce message I received. [snip] &lt;lisi.reisz(a)gmail.com&gt;om>: host alt2.gmail-smtp-in.l.google.com[74.125.141.27] said: 550-5.7.1 Unauthenticated email from yahoo.com is not accepted due to domain's 550-5.7.1 DMARC policy. Please contact administrator of yahoo.com domain if 550-5.7.1 this was a legitimate mail. Please visit 550-5.7.1 https://support.google.com/mail/answer/2451690 to learn about DMARC 550 5.7.1 initiative. h192si57227017vka.138 - gsmtp (in reply to end of DATA command) </quote> The email address in question is elsewhere said to be: deloptes(a)yahoo.com