After the update from NC 15.02 to 15.04 no emails will be sent via cron

The dispatch by test mail in the basic settings works and the test mail arrives immediately. Only the cronjob will no longer send emails to all users who have activated their settings in such a way that changes should always be communicated via email. The cronjob is also displayed as successful in the basic settings. This is also done with the right user “crontab -u www-data -e”. A server restart has also brought no success.
Can anybody confirm this?
Is this a new mistake?

Thank you.

Upgraded to v15.0.4 and mail notifications are working like expected.

Which settings are you using? Send notifcations each day or hour?

“As soon as possible”.
I also find no error messages. All logs are clean. Do you have an idea?

PS: I’ll set it up every hour. Let’s wait and see if that will help.

Is there actually a mail queue in NC? Then I could just take a look.

Unfortunately, there are still no emails. I just can not explain mkir that? Anyone else has an idea why could that be? I have just restored a backup with the version 15.02. I upgraded them from NC 14.06. Here was already the problem with the e-mails. So probably the email problem will be caused by the upgrade from 14 to 15. But what could it be?

People, please do not leave me hanging. I need help. Where are the cracks?
I have no idea. Even the mail when sharing a file goes out. Only the own notifications do not go out. So everything that has to do with the cron job (for example “Deck”).
Thank you.

Have any necessary tables been deleted after the upgrade? Which tables must exist in the database? I can only imagine that the tables are damaged or deleted.
Note: We only use LDAP users

I did not find the error per cron. But I have found another way that e-mails can be resent:

crontab -u www-data -e
*/15 * * * * php -f /var/www/html/occ activity:send-mails

It works again. I suspect that the App Deck causes errors in mail handling. If I enter the following, an error will be displayed in deck.
sudo -u www-data php -f /var/www/html/occ activity:send-mails

Does nobody use this app?

After emptying the mailq, the normal cron job will work again.
With that I could now remove the additional cron job again.
A weird mistake and a crazy workarount.
But good if it helps.
In any case, everything is back to normal.