Email notifications not consistent

We have email notifications activated, but it seems that sometimes notifications go out and sometimes they don't. Sometimes we will receive notification that we have a new message and will login to have a look and we are surprised that there are other messages from previous days in our inbox that we did not receive notification about. We have confirmed that these missing notifications are not being redirected into our spam mail folder.

So 2 questions:

1) is there a logfile or record somewhere that will show us that UddeIM indeed mailed a notification for a given message?

2) Is this a known issue with UddeIM email notificationsa and if so, is there a fix for it?

Running UddeIM 1.6 on Joomla 1.5.9

There is no "sometimes it works, sometimes not", either notifications are sent or not. uddeIM creates no logfile since you can check your server log file which is more reliable.

Some server have restrictions when messages are sent by local applications (e.g. PHP). So maybe its your server (or provider) that blocks messages.

There are no known issues in uddeIM 1.6 regarding email notifications. Nevertheless you should update to uddeIM 1.9 stable.