Faraday how to get returned parameter from a POST and update record?

Question

When a record is created in rails I am calling a Faraday rest post to a service. This service will return a ticketid of the newly created ticket. I want to then update the rails record with the returned ticketid. I am getting an error No Implicit Conversion of Hash into String I haven't been able to resolve when trying to access the returned ticketid. Here is my code:

url = 'https://URL.com'

conn = Faraday.new(url) do |faraday|
  faraday.request :json
  faraday.response :json, content_type: /\bjson$/

  # Adding headers
  faraday.headers['apikey'] = '1234'
  faraday.headers['Content-Type'] = 'application/json'
  faraday.headers['properties'] = 'ticketid'

  # Capture the response within the block
  response = faraday.post do |req|
    req.body = requestData.to_json
  end

  faraday.adapter Faraday.default_adapter

  if response.status == 201
    ticketid = JSON.parse(response.body)['ticketid']
    update(ticketid: ticketid) # Update the 'ticketid' attribute of the request record
  end
end