Home › Forums › Newsletter Plugin Support › Sending limit for Mailersend SMTP
- This topic has 16 replies, 3 voices, and was last updated 1 week, 1 day ago by
Adam_NZ.
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June 6, 2025 at 6:57 am #345136
Adam_NZ
ParticipantSince I’ve had problems with sending to Gmail accounts, I’ve installed the Mailersend plugin/module.
Single/test emails went out fine but when sending the full Newsletter (660 subscribers), I got a sending limit error … telling me I could only send 10 emails per minute.
How do I set that up in the Newsletter plugin, when I only have settings per hour and per second?
I had mine set to 540 and 0 – which would equate to 540 then 120 in the 2nd hour. What am I doing wrong?
TIA.
June 9, 2025 at 11:30 am #345194Michael
KeymasterHello,
you need to set 600 mails per hour in Newsletter’s settings.
Also take a look at Help > Delivery and check the statistics there to collect some real-world data on your sending speed.
June 11, 2025 at 12:18 am #345282Adam_NZ
ParticipantThanks for the info 🙂 … the error (and consequent block) was because the number of emails sent *per minute* [just] went over the maximum of 10 p/min. If I set 600/hr, does that automatically throttle sends to < 10/min? Also – what should I be setting the “per second” value to?
I can’t keep sending multiple tests, as subscribers that *do* get the mails are going to get annoyed – so I need to get this 100% correct before the next send (!!).
June 11, 2025 at 8:33 am #345287Stefano
KeymasterOk, it’s a bit tricky, but since you can send one email every 6 seconds, you can set the max emails per second to 0.1, it means every email will have a delay of 10 seconds.
To be precise you should set that delay as 1/6=0.16.June 11, 2025 at 8:35 am #345288Stefano
KeymasterHi, I forgot we have another option. You can define a constant in your wp-config.php:
define(‘NEWSLETTER_SEND_DELAY’, 6000);
it is a delay in milliseconds (6000 = 6 seconds) between each email.
S.
June 11, 2025 at 8:37 am #345289Stefano
KeymasterHere are a few other specifications:
https://www.thenewsletterplugin.com/documentation/developers/dev-newsletter-constants/#neewsletter-send-delayJune 11, 2025 at 8:39 am #345290Stefano
KeymasterAnd I go with the fourth message… There is a bug: you cannot, right now, set the speed to a decimal number (it will be converted to zero), you need to use the “define”.
June 11, 2025 at 9:26 am #345305Adam_NZ
ParticipantWow! I didn’t think it would be as complicated as it is (!).
I’ll go for the “define” method. A question, though … to achieve more than one email per second (but still stay under the <10/sec limit) would define(‘NEWSLETTER_SEND_DELAY’, 90); be the correct value? Would that be the equivalent of 9 emails/sec?
Having set that in wp-config.php what do I put in in the two plugin fields?
Thanks for all your help – much appreciated!
June 11, 2025 at 9:50 am #345308Stefano
KeymasterThe max emails per second field is ignored if the constant is defined. Please check if you see the constant listed with the correct value on Help/Status page. If not, be sure to retype the single quotes in the wp-config.php, since the copying and past breaks them.
If you set a delay of 90 milliseconds, you get 1000/90 email per seconds. To have 9 emails per seconds the delay must be 1000/9 milliseconds (111).
June 11, 2025 at 1:00 pm #345320Adam_NZ
ParticipantStefano … you’re a genius! I set it to 90 and risked a complete re-send.
Only 23% of the way through as I speak, but a couple of my test Gmail accounts have already got the newsletter (and no errors so far) – so .. looking good! 🙂
I’ll confirm the result tomorrow (bedtime here!) … and I hope this has helped other potential SMTP/Mailersend users.
June 12, 2025 at 3:58 am #345350Adam_NZ
ParticipantJust when I thought I’d nailed it … I got another error from Mailersend … I’d reach my daily limit of 1,000 request/sends! Their website doesn’t tell you when you initially set up the “Hobby” (free) plan what the per minute or per day limits are … you have to find out the hard way!
Even their plans comparison page makes no mention of the per minute restriction (though it does tell you about the daily limit).
So … I’m stuck with 1,000 sent out of a total of 1623.
However – we have another problem. On previous attempts to restart the send, the TEXT part of the HTML field was blank (though it’s set to “Autogenerate”) … so the send failed – and I could find no easy way of repopulating that info. On the current/suspended send, I see the same blank field, so daren’t attempt to continue the send.
It appears that, once a send has errored, there’s no way to restart it. Is that a bug?
How do I send the remainder of the list?
Can the newsletter send be split into 1,000 size chunks somehow? I suppose I could set the per hour limit to 40 (ie. 960 per day) but that seems ridiculously slow.
June 12, 2025 at 7:47 am #345353Stefano
KeymasterWhen an email has an error, you can edit and restart it.
The text part should not be deleted, that’s weird. Anyway, the missing text part does not compromise the sending (or, at least, I’m not aware of that “limit” by Mailersend).June 12, 2025 at 7:52 am #345354Adam_NZ
ParticipantI can confirm that the TXT section is cleared – it’s happened twice.
Unfortunately, Mailersend throws an error if it’s blank.
June 12, 2025 at 9:40 am #345357Stefano
KeymasterWhen the newsletter is paused for an error, you should be able to edit it, could you check if you can add back the text part, even a simple message, changing from autogenerate to manual?
June 12, 2025 at 9:56 am #345362Adam_NZ
ParticipantYes – I remember I could edit it – and was also thinking of placing some dummy text there, but it’d be nice if that field could be made to autogenerate the correct content somehow.
At the moment, when you look at that page, it gives the impression that the empty field will be auto-generated when the send is resumed … but that doesn’t happen.
June 12, 2025 at 9:57 am #345363Stefano
KeymasterHi, just tested with the Mailersend addon and every combination of text+html is accepted.
June 12, 2025 at 10:13 am #345364Adam_NZ
ParticipantThat’s right (thanks) … but how do I re-generate the correct info?
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