Sending too many emails at once

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Bilbo
Posts: 22
Joined: Sat Nov 07, 2015 5:18 pm

Sending too many emails at once

Post by Bilbo » Fri Feb 05, 2021 12:16 pm

Using VM Pro 2019.05. When it starts up, VM tries to send out allll the email reminders that would have been sent since the last time it was shut down. This could be fifty or more email messages, all at the same time. My ISP's mail server does not like that, thinking it is getting spammed. So their system automatically puts my IP address on a deny-list for a period of time. The first problem is, VM continues trying to repeatedly and quickly send all the reminders, and my deny-list timeout gets reset to zero. Next, my email program cannot sent email, until after I shut down VM and the timeout expires, and my IP address is automatically removed from the deny-list some hours-whatever later.

This situation was proven by telling VM to send email by connecting to an SMTP server inside my network, under my control. The local mail server forwards messages from VM to the ISP's mail server, but waits one minute between sending each message (that's the minimum setting available). This way, it takes several minutes for all the reminders to get sent to the ISP, but my IP address never lands on the deny-list, and my email program can send messages as usual. Running a local email server is not normal, and should not be required for VM to not-get my IP banned, even temporarily.

So. I propose VM to include a new config item under Options -> Email Settings -> Server and Logon Information called like "Delay between sending each reminder" or similar. VM would then wait this number of seconds before sending "the next" reminder email. The default could be zero, because that's the current behavior. The upper bound could be like 600 for a delay interval of ten minutes, or 255 to wait four minutes and fifteen seconds. A normal setting would be like five seconds. Basically you don't want VM to eat up the limit of 100 messages per minute/per hour set by the ISP. The whole idea is to avoid overloading any link in the chain of email delivery. Yes people can call the ISP and request their limit be raised, but this should not be necessary either.

Is there any version that already has this feature?

Also, a similar delay feature could be used before or between syncing calendars, as seen requested in other threads.

Bilbo
Posts: 22
Joined: Sat Nov 07, 2015 5:18 pm

Re: Sending too many emails at once

Post by Bilbo » Sat Feb 06, 2021 6:40 pm

Follow-up: For some reason, VM showed an error message like "cannot send email reminders because SMTP connection failed". Yet the destination mailbox contained several new reminder messages that had just arrived. How do VM's reminders both get sent and fail to get sent in the same session?

The clue was, the status bar quickly showed many "Sending reminder" messages, about many different events. Further, the status messages would pause, and then repeat themselves after less than five seconds. It looked like VM was trying to email a bunch of reminders, then when that failed, just re-trying the bulk-send right away. Clearly that's no good, because whatever was preventing emailing was not going to disappear so quickly.

Email forwarding services, or apps that send many messages, have throttling features built in, so as to not get shut out by the receiving email services, which are only trying to protect themselves from over-use or abuse or attack in any form. So, VM I suggest should have a way to increase/control the timeout before re-trying a previously-failed SMTP connection, in addition to the feature of throttling the delivery rate per message.

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VueSoft
Dan Chartrand
Posts: 3929
Joined: Sat Aug 23, 2008 12:39 am
Location: St. Louis, Missouri, USA
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Re: Sending too many emails at once

Post by VueSoft » Mon Feb 08, 2021 12:03 am

Hi Bilbo, thank you for the feedback. I'll improve VueMinder to throttle the number of email reminders per minute that it tries to send, and to delay a bit before it tries sending an email reminder again, if the previous attempt failed. I'll post a reply when these improvements are completed.
Dan Chartrand, Founder
VueSoft LLC | St. Louis, Missouri, USA

User avatar
VueSoft
Dan Chartrand
Posts: 3929
Joined: Sat Aug 23, 2008 12:39 am
Location: St. Louis, Missouri, USA
Contact:

Re: Sending too many emails at once

Post by VueSoft » Sat May 08, 2021 4:39 pm

Hi Bilbo, version 2021.02 has been released. This version will limit the number of email reminders sent per minute and will delay 1 minute before attempting to send a failed email reminder again. To update, click the "Help -> Check for Updates" menu command.
Dan Chartrand, Founder
VueSoft LLC | St. Louis, Missouri, USA

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