Need help in using REST API.

I am trying to fetch the keywords having a specific category value from RQM .

I am using teh below Feed url

https://<rqmserver>:9443/qm/secure/service/com.ibm.rqm.integration.service.IIntegrationService/resources/<projectname>/keyword?fields=feed/entry/content/keyword/category[@term='<Categoryterm>' and @value='<categoryvalue>']

I am getting below error.
****ERROR: Get request failed: HTTP/1.1 505 HTTP Version Not Supported****

My RQM version is 4.0.3. According to teh below document filtering using Category in Keywords is allowed in RQM 4.0.3.

https://jazz.net/wiki/bin/view/Main/RqmApi

Please help me if am missing any thing. Thanks in Advance.