HP Service Manager 9.20 Email Sending Error

We have a custom workload involving HP Service Manager 9.20 however we are hitting a problem where we are trying to send out outgoing mails from the service .

The Main HP SM9 Threads are not throwing outputs however we are getting the error when we try to shoot outgoing mails from the service. These emails use a custom HP Scenario (.scn file) and to call a wsdl with an exchange server configured.

Error :
[(RetrieveEmailList_Request) RetrieveEmailList] (0) Cause by org.apache.axis2.AxisFault: Request Response Size Exceeds Java Memory Threshold.

Awkwardly the incoming e-mails do not throw up the same error only the outgoing emails do but the queue is a lot lesser on those scenarios , we have over 1000 emails in the outgoing queue.

Please suggest if it is possible to increase the java heap size somehow or take a backup of all waiting emails from the application and delete the same to decrease the queue length if the queue is taking up the java memory. (We are running a 32 bit java version and it seems hp sm is also 32 bits only)

Please assist , any help is greatly appreciated