PhonePeException: code=KEY_NOT_CONFIGURED, message=Key not found for the merchant

Question

When i'm initiate the transaction using the pay function:

@GetMapping("/initiate")
    public String initiatePayment() {
        String merchantId = "M15IHWI5YI3Y";
        String merchantTransactionId = UUID.randomUUID().toString().substring(0, 34);
        long amount = 100;
        String merchantUserId = "MUID1234";
        String callbackUrl = "https://api.dolby.com/media/webhooks";
        String redirectUrl = "https://sharkdom.com/";
        String redirectMode = "REDIRECT";

        System.out.println("phonepeClient------------------->" + phonepeClient);

        PgPayRequest pgPayRequest = PgPayRequest.PayPagePayRequestBuilder().amount(amount).merchantId(merchantId)
                .merchantTransactionId(merchantTransactionId).callbackUrl(callbackUrl).merchantUserId(merchantUserId)
                .redirectUrl(redirectUrl).redirectMode(redirectMode).build();
PhonePeResponse<PgPayResponse> payResponse = phonepeClient.pay(pgPayRequest);

Error:

PhonePeException(super=com.phonepe.sdk.pg.common.http.PhonePeException: , responseCode=400, phonePeResponse=PhonePeResponse(success=false, code=KEY_NOT_CONFIGURED, message=Key not found for the merchant, data={}))

How to solve it