Duplicate Emails Send When a Lot of Recipients

Hi @luke-williamson,
Thanks for your message.

There are usually a couple of reasons that duplicate notifications occur:

1. It takes too long for the server to send all the notification emails.
2. Another plugin is hooking into the public/update action (such as a social sharing plugin).
3. There are too many users to send to in one go for the server/email plugin to handle.

Do you think any of these could apply to you?

Hey there, thanks so much for responding to my issue so soon!

1. When the post is published it takes about 40 seconds for the post editor page to complete loading (whilst it sends out the emails)
2. I don’t have any other plugins that intervene with the plugin’s update function (including 0 social plugins)
3. I only have 86 WordPress users that this newsletter actually sends to, so surely that’s not the issue either?

Please let me know if I can help in any way, I’d be happy to help if possible.

Thanks!

I have the exact same issues on my site. Any possible workarounds appriciated.

Hi @luke-williamson,
Thanks for clarifying.

Are you using an SMTP plugin?
Sending to 86 users shouldn’t make you wait 40-seconds for the emails to send. Is is possible your server under-powered?

@resrutt How many users are you sending to?

Hey @voltronik no I’m not using an SMTP plugin.

My server has 4GB Physical Memory Usage and I’m not sure why server performance would ever be an issue when it comes to something like this.

Any possible solutions or available fixes would be great. Otherwise I am unable to use this for future post published email notifications as each time it has cost us numerous unsubscribes. :\

Hi @luke-williamson,
It might be worth trying an SMTP plugin to see if this irons out any issues with wp_mail.
I recommend Post SMTP because it comes with an email log.

Providing that you’ve ruled out a plugin or theme conflict adding to the post publish/update process then I’m not sure why it would be sending duplicates. In my experience, duplicates are only ever caused by either the server or a plugin conflict.

Have you tried using a single user (such as a dummy user with a no-reply email address) in the Send To field whilst adding the remaining users in the BCC field?
This would essentially send a single email but with all the other users BCCed in.
One caveat is that you won’t be able to use the global user shortcodes though.

@voltronik I installed that plugin and had the logging set up too. I published a new post and it logged 176 emails going out (exactly half of my 88 subscribers). I could see duplicate email address recipients in the logging.

I also measured my server CPU whilst it took 60(ish) seconds to publish the post, it only ever reached 70% CPU at maximum.

I have a separate notification rule set up already that sends me an admin notice email every time a new post is published. This email only sends to myself once, unlike the email subscribers one.

Do you have an email address I could reach you at? I’d be happy to provide you logins if that helps investigating this issue.

Hi @luke-williamson,
Thanks for the extra info.

I can’t provide that level of support via email, etc. unfortunately.

At this point, I think your best bet would be to run through this document and see how you get on.

Hi @voltronik after going through some of the documentation and testing with bulk test imported users, it seems to only send duplicate emails when I have WP Rocket activated.

Do you think it may be possible in future to make this play nice with that? As it’s one of the most popular caching plugins out there and my site won’t be fast without it activated.

Thanks.

Hi @luke-williamson,
Ah, that’s the issue!

WP Rocket is listed as a known issue on this page: https://betternotificationsforwp.com/known-compatibility-issues/

I’ve been in touch with WP Rocket but they’ve been unable to find an issue at their end. Most other caching plugins work fine though.

Hey @voltronik,

Ahh! I didn’t see that page earlier.

Thank you for your assistance, I’ll contact WP Rocket also regarding this issue.

Hi @luke-williamson,
No probs.

Let me know how you get on.

I also use WP Rocket. I guess case closed, but without an actual solution. ??

Just a head’s up I’ve been in touch with WP Rocket and they said that they “pinpointed WP Rocket’s cache clearing function as the culprit. This is called after WordPress’s cache of a post is cleared.”

The staff member working with me to replicate this issue has been super helpful. Once this issue has been fully addressed I’ll post back here.

Thanks @luke-williamson,
That’s really helpful ??