... and email is working when generating alerts ?
... very strange.

Could you check email for special characters, others than @.
Maybe you can also try and send email to single address (your own for instance)

Hello,
I tested with a single email and it is the same error message

I just saw that I did not receive all the emails sent by project yesterday at 00:00
View Screenshot

I will do another test I will change SMTP server to be sure it is not the mail server that kidding and I will inform you

What is strange is that some emails are correctly sent.
Not all fail.
So I would bet on SMTP server or more possibly some network issue (possibly some proxy playing with connections)

after test with hostinger.fr smtp server

Logs:
---------------------------------
2015-06-24 16:15:42.269 ** ERROR ** Error sending mail
2015-06-24 16:15:42.269 ** ERROR ** SMTP Server : mx1.hostinger.fr
2015-06-24 16:15:42.269 ** ERROR ** SMTP Port : 25
2015-06-24 16:15:42.270 ** ERROR ** Mail stored in Database : #713
2015-06-24 16:15:42.270 ** ERROR ** PHPMail error : SMTP Error: The following recipients failed: cxxxmail@gmail.com
2015-06-24 16:15:42.270 ** ERROR ** PHPMail debug :
2015-06-24 16:15:48.869 ..... SCRIPT .... 10.xxx.xx.xx4 /view/objectDetail.php
2015-06-24 16:15:48.870 ..... SCRIPT .... 10.xxx.xx.xx4 Page=objectDetail.php
2015-06-24 16:15:48.914 ..... SCRIPT .... 10.xxx.xx.xx4 ->/view/objectDetail.php
2015-06-24 16:15:48.928 ..... SCRIPT .... 10.xxx.xx.xx4 ->/view/objectButton.php
2015-06-24 16:15:48.937 ..... SCRIPT .... 10.xxx.xx.xx4 ->/tool/getObjectCreationInfo.php
2015-06-24 16:15:48.962 ..... SCRIPT .... 10.xxx.xx.xx4 drawTableFromObject(obj, included=, parentReadOnly=)
2015-06-24 16:15:49.089 ..... SCRIPT .... 10.xxx.xx.xx4 drawTableFromObject(obj, included=1, parentReadOnly=)
2015-06-24 16:15:59.238 ..... SCRIPT .... 10.xxx.xx.xx4 /tool/sendMail.php
2015-06-24 16:15:59.239 ..... SCRIPT .... 10.xxx.xx.xx4 Page=sendMail.php
2015-06-24 16:15:59.280 ..... SCRIPT .... 10.xxx.xx.xx4 ->/tool/sendMail.php
2015-06-24 16:15:59.358 ..... SCRIPT .... 10.xxx.xx.xx4 sendMail_phpmailer
2015-06-24 16:16:00.585 ** ERROR ** Error sending mail
2015-06-24 16:16:00.585 ** ERROR ** SMTP Server : mx1.hostinger.fr
2015-06-24 16:16:00.585 ** ERROR ** SMTP Port : 25
2015-06-24 16:16:00.585 ** ERROR ** Mail stored in Database : #714
2015-06-24 16:16:00.585 ** ERROR ** PHPMail error : SMTP Error: The following recipients failed: pxxxmo@gmail.com
2015-06-24 16:16:00.585 ** ERROR ** PHPMail debug :
2015-06-24 16:16:26.285 ..... SCRIPT .... 10.xxx.xx.xx4 Page=checkAlertToDisplay.php
2015-06-24 16:17:26.423 ..... SCRIPT .... 10.xxx.xx.xx4 Page=checkAlertToDisplay.php
----------------------------------
Firewall ok mx1.hostinger.fr port 25

It is not a connection error, the smtp server responds.
The mail server just refuses to send to emails to the recipients.
Maybe it is an anti spam functionality of the smtp hosted server.

hello
mail notification work fine with projeqtor V5.0.1

Thanks for all

Stange as there was no change about email notification on this patch.
Maybe it was some deployment issue fixed by new installation...

Anyway, happy to know your problem is solved.