Updating customer metafields is failing

[NicoSpoke]

Up until recently I was able to update a customers metafields by using the `{shop.url}/a/custmeta` endpoint. However, it recently started to return this error:

{"status": "ERROR", "message": "global name 'SHARED_SECRET' is not defined", "traceback": "['Traceback (most recent call last):\\n', '  File \"./app/mapp/proxy/views.py\", line 261, in handle_valid\\n    shopify.Session.setup(api_key=API_KEY, secret=SHARED_SECRET)\\n', \"NameError: global name 'SHARED_SECRET' is not defined\\n\"]"}

This is our script:

  return post({
    params: {
     'customer[id]': 000000000,
     'metafield[customer.mail_marketing]': true
    },
    then: ({status}) => {
      if (status === 'OK') {
        console.log('Succeded')
      } else {
        console.log('Failed')
      }
    },
    url: '{shop.url}/a/custmeta'
  })

What could be causing the above script to fail? It seems this has started to failed the last 2-3 days.

Thank you