Update worker manager throwing 404 error

Error while calling Update worker manager API.

Sometimes I'm getting 404 and sometimes I'm getting 200 OK.

status=404, reason=Not Found}}]]></ns0:errorPath>unsafe:ns0:instance<![CDATA[.The HTTP 404, 404 Not Found, and 404 error message is a Hypertext Transfer Protocol (HTTP) standard response code, in computer network communications, to indicate that the client was able to communicate with a given server, but the server could not find the resource that was requested. Carefully re-examine the target endpoint that is being called. ]]></ns0:instance></ns0:errorDetails></ns0:APIInvocationError> ]

Using details mentioned in below URL

REST API for Oracle Fusion Cloud HCM - Update an assignment manager