How to properly send a GraphQL update request using Axios? - node.js

Question

I created an application using AWS Amplify, and I want to create an endpoint in an API function that will mutate a field in GraphQL. Since its a nodejs API function, I cannot use the recommended libraries from the AWS documentation which use ES6, since the functions can only use ES5. Therefore I need to use Axios.
I created a graphql query:
const query = /* GraphQL */ `mutation updatePublication($id: ID!, $keywords: String) {
updatePublication(id: $id, keywords: $keywords){
id
keywords
}
}`
Next, I created the Axios request based on this StackOverflow question.
const data = await axios.post(
process.env.API_APPNAME_GRAPHQLAPIENDPOINTOUTPUT,
{
query: query,
variables: {
id: variableWithID,
keywords: "updated keywords!"
}
},
{
headers: {
'Content-Type': 'application/json',
'x-api-key': process.env.API_APPNAME_GRAPHQLAPIKEYOUTPUT
}
}
)
When I run the query, I get a status 200 from the server with the following errors:
data: null,
errors: [
{
path: null,
locations: [Array],
message: "Validation error of type MissingFieldArgument: Missing field argument input # 'updatePublication'"
},
{
path: null,
locations: [Array],
message: "Validation error of type UnknownArgument: Unknown field argument id # 'updatePublication'"
},
{
path: null,
locations: [Array],
message: "Validation error of type UnknownArgument: Unknown field argument keywords # 'updatePublication'"
}
]
}
Can anyone advise on what this means?