Have submitted this already via a ticket, but haven't received any response, wondered if anybody on the forum has an idea of how to fix the issue as described below

Trying to use the filter system to send mails but it is not working. This is what I am doing..

I go to subscribers, then filter newsletter, then filter by field, click filter and then "select filtered subscribers". Once filtered and selected i then choose send the page loads the messages which i select the correct message, click send again and then it takes me to the next page to finalise settings.

However with a few emails it works fine but sending 333 mails for example i get an internal server error.

Checking the status of the database i notice that the query is running but after 300 seconds an internal server error occurs.

The query run starts

select distinct (`idlist` ) from rsmail_subscribers where `subscriberemail`

I run a dedicated server on apache using plesk, have set very high limits in php memory and script execution.

If i run a send normally it works fine, but sending using a lot of subscribers via subscriber filter does not work without internal error.

The team at namesco (who are excellent trouble shooters) cannot see any issue as to why it wouldn't do it. THey have tried to optimize the database but that has had no effect.

Script is still running at 9000 seconds and causing site issues which means I have to kill the query in status.

How do I fix this?