TypeError: Invalid character in header content ["Location"]

val url = "https://api.tosspayments.com/v1/payments/confirm"
var headers = HttpHeaders()
val base64Key = Base64.getEncoder().encodeToString(secKey.toByteArray())
val auth = "Basic " + base64Key
headers.set("Content-Type", "application/json")
headers.set("Authorization", auth)
var contents = "{\"paymentKey\":\"${params.paymentKey}\",\"orderId\":\"${params.orderId}\",\"amount\":${params.amount}}"
val request = HttpEntity(contents, headers)
val response = rt.postForEntity(url, request, TossPaymentResponse::class.java)