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Member Since 07 Dec 2006
Offline Last Active Jan 19 2022 07:43 PM

Posts I've Made

In Topic: Error Message Could Not Be Sent. Mailer Error: Smtp Connect() Failed. Https:/...

13 January 2022 - 10:22 PM

Yes it feels like some kind of rate limiting feature, though it starts to happen on low volumes of around 10 emails.


I have a feeling it can be fixed by following the instructions here.



In the meantime we got it working with an SMTP relay service https://www.sendinblue.com/which is working well and not costing anything for our email volumes.


It would be nice to have it running natively through Office 365 but I know that will take a lot of time and trial/error to get going...

In Topic: Error Message Could Not Be Sent. Mailer Error: Smtp Connect() Failed. Https:/...

10 January 2022 - 04:10 AM

"Office 365 for smtp .. that is a whole other problem."


Yes it seems so...


We've been using phpMailer (on VPS server) for years then it suddenly stopped working. It looks as though SMTP is a better option anyway so we have been trying to get it working properly for a few weeks now.


It seems to work about half of the time (when clicking "notify customer") and saving the order until it gets progressively worse then won't work at all. Until the next day and it does the same thing again. When it fails we get the message "Mailer Error: SMTP connect() failed."


We're using the recommended SMTP settings for O365, e.g.




password (has been verified as correct)

Encryption connection - TLS

Use SMTP authentication - ticked


In Exchange Admin center > Settings > Mail flow > Security....


Turn on SMTP AUTH protocol for your organisation – Enabled

Turn on use of legacy TLS clients – Disabled


In Microsoft 365 admin center > Active Users > User > Mail tab > Email apps > Manage email apps > We have Authenticated SMTP ticked.


We're on V4.3.6


Any ideas?