After providing filters the portlet is spinning for 15 mins and showing "Error 500 - Internal Server Error. The Server could not retrieve the document due to server-configuration or the other technical problem. Contact your administrator."
Is this because the Query crossing any session time ?
You will need to look in the application log files (app-ca.log) on the server to have any idea about the causes.
The message you are seeing is too generic to determine anything.
After providing filters
Does that mean that without filters it works?
If it does, then test one filter field at a time to see if you can detect a problem filter field.
Cross-linking duplicate question thread:
Portlet showing Error - 500. Internal server error.