Forwarding MYLDSMAIL messages to gmail address

[86Bengal]

My son is a current, full-time missionary, and happily he writes to us each week. At his suggestion, I set up an auto-forwarding rule on my email account to automatically forward his weekly letters to a few other family members and friends. This worked perfectly for about 7-8 months. But recently, one of the destinations has been failing. Here is today's error message (identical to other weeks):

The attached message could not be delivered to the recipients listed below.
The original message was rejected at Mon, 31 Jul 2017 22:01:01 +0000
Delivery attempt from MAG: smtp754.redcondor.net to receiving MTA failed.
----- The following addresses had permanent fatal errors -----
<xxxxxxxxxxx@gmail.com>
550-5.7.1 Unauthenticated email from myldsmail.net is not accepted due to
550-5.7.1 domain's DMARC policy. Please contact the administrator of
550-5.7.1 myldsmail.net domain if this was a legitimate mail. Please visit
550-5.7.1 https://support.google.com/mail/answer/2451690 to learn about the
550 5.7.1 DMARC initiative. b1si22491pld.336 - gsmtp

The address X-ed out above is my son's correct gmail address. The forwarding rule works successfully with a couple of other gmail addresses. I don't know how to contact the administrator of myldsmail.net as suggested to see if they can correct anything on that end. I read the google.com link, but didn't find any info I found helpful.

Does anyone have any ideas on what could fix this? Thanks.

[johnshaw]

It's the receiving end that you'll likely need to get addressed. I doubt seriously that you'd ever find the person responsible for my.ldsmail.net, neither will they likely make the changes you need.
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My suggestion is that whoever's mail is failing has some kind of security enabled and they can 'white-list' your son's email. If he wants the email have him configure his gmail account to correctly be delivered.

[russellhltn]

I'm puzzled why the receiving system is flagging your son's email when your doing the forwarding. It should be trying to authentic you as the sender, not your son.

[johnshaw]

I read that as he setup the forwarding from his son's account, but maybe that was a bad assumption.

[86Bengal]

Son #1 is the missionary that's writing emails to be shared throughout the family. He sends them to me (dad), and my auto-forwarding rule passes them on to a dozen or so family members. Son #2 has the Gmail account that the messages aren't getting through to. But Grandma and Grandpa also have Gmail addresses that reliably receive the emails.

Like russellhltn, I'm also surprised that Son #1's address appears to be treated as the source in the error message, when it's my email that's being rejected. (My address is not of an lds or gmail domain.)

I'll try having Son #2 white-list both me and Son #1 to see if that helps.

[aclawson]

This is an anti-spam feature: either SPF or DKIM or both are causing the problem. You can try to ask google support for help, otherwise search for solutions that others have found.