I took a quick look at the supplied log file and it looks like some of these did successfully deliver:

and some of them have failed:

While some of them failed due to authentication issues while sending: 

So it looks like delivery of these messages is failing for a variety of reasons. I'd recommend first ensuring you have the following DNS requirements properly deployed to ensure messages are delivered accordingly: 

The biggest concern I would have here is that your messages may be getting routed to the junk mail folder on these hosts due to your existing DNS setup (DDNS being used) not supporting SPF/DKIM deployment. Unfortunately this isn't something that has a simple answer as the reason for failures is varied. 

Once you've double checked your DNS settings, try setting up a couple of test mailboxes at the hosts you're having trouble delivering to, then complete some mailing list deliveries to these mailboxes so you can check the SMTP/Delivery logs for the specific cause of failure. 

I hope that helps! Have a great rest of your week.

Attention: Kyle Kerst:

     Thank you ( see Colossians 3:15, for example ) for your response.  I just saw it this morning.  Included with this post are three Paint 3D tempsnip image files ( below ) for your consideration.

This one shows my domain name service ( DNS ) "A," "AAAA" ( IPv6 ), and mail exchange ( MX ) records for my dynu.com domain name ( i.e., "theholybible1.ddnsfree.com" ).  Currently there is a blue pencil icon and a "not allowed" symbol ( not pictured ) in the "Actions" column associated with my MX record ( enclosed in the first red rectangle, above ).  I suppose I could click on the above-mentioned "not allowed" symbol to activate the MX record ( which would produce a green check mark in that column associated with the MX record ).  The two canonical name ( CNAME ) DNS records ( enclosed in the second red rectangle ) are configured for my SMTP2Go.com smtp service, which is being used with other e-mail clients.  The second above-mentioned image file is as follows:

This one shows the bottom portion of the same DNS settings page indicated in the first image file ( above ).  The first two TXT DNS records ( of the three indicated in the red rectangle, above ) are the domain keys identified mail ( DKIM ) DNS records.  The third TXT DNS record is the sender policy framework ( SPF ) record, which is currently configured for my above-mentioned SMTP2Go.com smtp service.  If I remember correctly, there are tools available at the above-mentioned dynu.com web page which can be used to help determine the proper configuration for SPF DNS records, for example.  Whatever the case may be, the third above-mentioned image file is as follows:

This one shows an e-mail alias e-mail message that was successfully sent this morning-the name of that SmarterMail Free Edition version 15.7.6885 private e-mail server e-mail alias is "Bulletin1" ( it is enclosed in a red rectangle ). At this point, I suppose that I could configure another SPF record in my dynu.com DNS settings page, but why would I need to do this?  I have just provided evidence that one of my SmarterMail private e-mail server e-mail aliases is working.  There is not much difference between an e-mail alias and a mailing list ( except that with a mailing list, users have the option of subscribing to- or unsubscribing from it ).  Therefore, since my e-mail aliases are working fine, then my mailing lists should be working fine as well.  Let me know of any suggestions that you have.  Thank you for your help and your patience.  Keep in touch.

Sincerely in Christ,

Russell E. Willis

P.S. - Please read Proverbs 23:23.

"23 Buy truth, and do not sell it; buy wisdom, instruction, and understanding."

[ Proverbs 23:23; RSV ]

Russell E. Willis

3559 Almanac Road

Tallahassee, Florida  32309

Hello Russell. Thank you for the reading material :-) I'm still reviewing your environment, but from the screenshots you provided this appears to be set up correctly. As such, I checked the email blacklists to see if by chance you were listed here, and I did find you on one list: Spamhaus Zen. I've included the delist request link below:

After removing that blacklisting I recommend trying to send email again to Gmail and other larger providers to see if this helped. If it did not, one thing you can try that I've seen work in some cases is to send email from your server to a variety of accounts on Gmail, Outlook, etc, opening each of the received messages in the Spam folder and clicking the "Not Spam" button. Doing this enough times will help remove your IP address from the internal blacklists they maintain as well.

Lastly, if none of the above works this may be related to the IP address set up you have in place. While you have SPF/DKIM all set up, you are ultimately using a dynamic IP address and this is flagged as potentially hazardous by larger email providers due to spam networks frequently operating this way.

If all else fails; setting up a t2.micro server on Amazon's AWS cloud server network would allow you to avoid a lot of these issues and not have to use a dynamic IP address services to accomplish it. On top of that, the t2.micro servers cost just dollars a month to operate. Just some ideas, hope that helps!

Attention: Kyle Kerst:

     Thank you ( see Colossians 3:15, for example ) for your latest response.  Included with this post are two Paint 3D tempsnip image files ( below ) for your consideration.  The first one is as follows:

This one shows the new sender policy framework ( SPF ) domain name service ( DNS ) record that I created and activated this morning ( it is enclosed in the first red rectangle, above - the text for that record is: "v=spf1 mx a ptr ip4:67.235.205.139/32 ?all" ).  This DNS record was created with the help of the "SPF generator" tool on the dynu.com web page.  In the second red rectangle ( above ), you will find the mail exchange ( MX )- and pointer ( PTR ) DNS records.  Since the MX record already existed, I simply activated it this morning.  I created the PTR DNS record myself by following the instructions at the following web page: "https://www.itworld.com/article/2833006/how-to-setup-reverse-dns-and-ptr-records.html" ( the text for this record is: "205.235.67.in-addr.arpa" ( this web page provided easy-to-follow instructions )).  The second above-mentioned image file is as follows:

This one shows information regarding the "SPAMHAUS PBL Self-Service IP Removal" process.  The information in the red rectangle ( above ) clearly indicates that the PBL list is not preventing me from sending my e-mail messages - it suggests that simple mail transfer protocol ( SMTP ) authentication may be the problem ( see also the following paragraph on that web page ).  I doubt that smtp authentication is causing my problem, since I am able to send e-mail messages successfully from my SmarterMail Free Edition version 15.7.6885 private e-mail server and, as indicated in my previous posting, I am able to successfully send e-mail messages using one of my e-mail server e-mail aliases ( which are not that much different from a mailing list ).  There is something else ( or, possibly, someone else ) preventing me from successfully sending e-mail messages with my mailing lists.  Also, I doubt that I really needed to activate the above-mentioned MX DNS record, or to create the new SPF- and PTR DNS records, but at least it was a learning experience for me.  Let me know if you have any additional suggestions.  Keep in touch.

Sincerely in Christ,

Russell E. Willis

P.S. - Please read Proverbs 23:23.

"23 Buy truth, and do not sell it; buy wisdom, instruction, and understanding."

[ Proverbs 23:23; RSV ]

Russell E. Willis

3559 Almanac Road

Tallahassee, Florida  32309