SharePoint Task notification and subscription mails not being sent

I seem to be having the following problem with a client – mail is sent out when user creates task (task initiator) but does not send out for any type of notification including alerts or task alerts and subscriptions

The following process was followed to attempt to resolve the issue based on prior investigation:

– Ensured workflow notification emails were enabled in central administration application management

– Ensured central administration was using correct mail server to send out mail

– Ensure that task lists were set up to send mail eg. email notification set to ‘Yes’

– Am awaiting confirmation from the mail administrator but checked db event logs so not sure if it’s sending mails although table “ImmedSubscriptions”  have entries contained within them but table “EventCache” have no entries regarding the mails to be sent out as explained in the following blog

– alerts dont seem to work on any list or document library neither does the mail notification task alert on any newly created list or document library, eg after a new task list is created for workflow the mails still don’t seem to send, assuming there might be permission restrictions mentioned in this forum

– Had a look through the following site and site2 as well to attempt their resolutions/configuration

–  reran configuration wizard on the server and notification mails still not coming through after retesting all notification mail options

– ran the WSS V3 service pack 1 update and tested notification mails which still not coming through

– ran the office infrastructure service pack 1 and still nothing ?

– ran the following command to reset the templates: stsadm -o updatealerttemplates -url http://testserver -f "c:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\XML\alerttemplates.xml" -LCID 2057 and completed an IISRESET and still nothing is being sent or received for and on this machine

Understanding of the situation is at the state that all notification mails excluding the workflow initiation mails are not being sent out. So this is then not a workflow issue but a general notification mail problem.

– Came across the following post which I have yet to attempt: Microsoft site and Egghead Forum – and will update the post if any progression is made

If anyone has any other suggestions or a possible solution I’d be happy to hear it.