Error 500 in REST API load test userpath test

Please help me with the below error

HTTP/2.0 500
Content-Length: 0
expires: Thu, 01 Dec 1994 16:00:00 GMT
cache-control: no-store, no-cache=set-cookie
content-type: text/html;charset=ISO-8859-1
content-language: en-US
x-cnection: close
x-heist: lS7xC6pDGsBdopbD
date: Wed, 24 Mar 2021 13:00:38 GMT
set-cookie: LBCSS2=********************; Path=/
set-cookie: ********; Path=/
strict-transport-security: max-age=****
x-robots-tag: noindex, nofollow