draftOrderCreate graphQL mutation failing suddenly

Retired Boards Appdev Graphql Basics And Troubleshooting
3

we’re receiving the same error! suddenly out of nowhere all our orders started failing since draft orders were not getting create on Shopify.

our input parameters are:

{shippingAddress:{zip:"POSTCODE",phone:"+4412345678",lastName:"X",firstName:"X",country:"GB",city:"London",address2:null,address1:"X"},lineItems:[{variantId:"Z2lkOi8vc2hvcGlmeS9Qcm9kdWN0VmFyaWFudC8zMTc4MjM5MTc3NTI2Nw==",quantity:1,appliedDiscount:{valueType:FIXED_AMOUNT,value:2.26,title:"Discount",amount:"2.26"}},{variantId:"Z2lkOi8vc2hvcGlmeS9Qcm9kdWN0VmFyaWFudC8zMTYxNDg1MjMwMDgzNQ==",quantity:1,appliedDiscount:{valueType:FIXED_AMOUNT,value:2.700000000000001,title:"Discount",amount:"2.700000000000001"}},{variantId:"Z2lkOi8vc2hvcGlmeS9Qcm9kdWN0VmFyaWFudC8zMjA0NTUzNTIzMjAzNQ==",quantity:1,appliedDiscount:{valueType:FIXED_AMOUNT,value:2.0,title:"Discount",amount:"2.0"}},{variantId:"Z2lkOi8vc2hvcGlmeS9Qcm9kdWN0VmFyaWFudC8zMTYxNDg0OTQ1MDAxOQ==",quantity:1,appliedDiscount:{valueType:FIXED_AMOUNT,value:2.5,title:"Discount",amount:"2.5"}}],billingAddress:{zip:"POSTCODE",phone:"+4412345678",lastName:"X",firstName:"X",country:"GB",city:"London",address2:null,address1:"X"},email:"email@provider.com"}

the graphql requst is:

draftOrderCreate(input: #{input}) {
          userErrors {
            field
            message
          }
          draftOrder {
            id
            totalPrice
            totalShippingPrice
            totalTax
            subtotalPrice
            lineItems(first: 250) {
              edges {
                node {
                  id
                  quantity
                  variant {
                    id
                  }
                }
              }
            }
          }
        }

And the response is:

"data" => %{
       "draftOrderCreate" => %{
         "draftOrder" => nil,
         "userErrors" => [
           %{"field" => nil, "message" => "Invalid input arguments."}
         ]
       }
     },
     "extensions" => %{
       "cost" => %{
         "actualQueryCost" => 10,
         "requestedQueryCost" => 10,
         "throttleStatus" => %{
           "currentlyAvailable" => 990,
           "maximumAvailable" => 1.0e3,
           "restoreRate" => 50.0
         }
       }
     }
   },

it suddenly happened today around 4/5PM GMT+1 (London time). we haven’t changed/touched this since 2019.

What is going on? We have a live app and it’s crucial for us to get this fixed. We spoke to the support but they haven’t come back to us with a solution just yet