GraphQL mutate operation failed. NonRetryableException{message=OkHttp client request failed., cause=null, recoverySuggestion=Irrecoverable error}

Graphql mutation operation fails in android but works in AppSync console

Error:

GraphQL mutate operation failed
E/amplify:flutter:api( 4899): NonRetryableException{message=OkHttp client request failed., cause=null, recoverySuggestion=Irrecoverable error}
E/amplify:flutter:api( 4899): at com.amplifyframework.api.aws.AppSyncGraphQLOperation$OkHttpCallback.onResponse(AppSyncGraphQLOperation.java:145)
E/amplify:flutter:api( 4899): at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:519)
E/amplify:flutter:api( 4899): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
E/amplify:flutter:api( 4899): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
E/amplify:flutter:api( 4899): at java.lang.Thread.run(Thread.java:920)
W/AtomicResult(mutate)( 4899): Attempted to send success value after initial reply
I/flutter ( 4899): ApiException(message: OkHttp client request failed., recoverySuggestion: Irrecoverable error, underlyingException: null)

code:

Product product = Product(
    name: 'Product1',
    description: "description",
    price: 20,
    type: ProductType.fruit,
    postType: PostType.sell,
    userID: user.userId);

try {
  final req = ModelMutations.create(product);
  var res = await Amplify.API.mutate(request: req).response;
  print(res.data);
} catch (e) {
  print(e.toString());
}

Schema:

type User @model @auth(rules:[{allow:owner,operations:[create,update]}]){
id: ID!
name: String!
email: String!
product: [Product] @hasmany(indexName:"byUser",fields:["id"])
}

type Product @model @auth(rules:[{allow:owner,operations:[create,delete]}]) {
id: ID!
name: String!
description: String!
price: Int!
type: ProductType! @Index(name:"byProductType")
postType: PostType! @Index(name:"byPostType")
userID: ID! @Index(name:"byUser")
}

enum PostType{
sell
buy
}

enum ProductType{
vegetable
fruit
spice
other
} ```