erpintegrations rest api used submit ESS based custom BI report,multiple try to submit it giving -1

HI,

we are using Below rest api to submit custom bi report ESS job. we are trying submit sequentially twice. first request returning request id, second request it returning request id -1, if we set time delay between request. second request working fine. (we are using MuleSoft has integration platform).

https://CloudURL/fscmRestApi/resources/11.13.18.05/erpintegrations

Request payload first request giving "ReqstId" : "781167",

second request payload request "ReqstId" : "-1", Kindly advise. how we can resolve issues without time delay between two requests.