Google Sheets API: Error 400: redirect_uri_mismatch

Question

I keep getting Authorization errors when sending a POST request from my React/Ruby app. I'm getting different errors depending on what OOB_URI I'm using.

If I use OOB_URI = "urn:ietf:wg:oauth:2.0:oob".freeze then I get the following error:

When I use OOB_URI = "http://127.0.0.1".freeze then I get the following error:

Here's my Ruby code

require "google/apis/sheets_v4"
require "googleauth"
require "googleauth/stores/file_token_store"
require "fileutils"

# Get authorization
OOB_URI = "urn:ietf:wg:oauth:2.0:oob".freeze
# OOB_URI = "http://127.0.0.1".freeze
APPLICATION_NAME = "mimirgettingmarried".freeze
CREDENTIALS_PATH = "/Users/michelleroos/Desktop/mimirgettingmarried/mimirgettingmarried/config/credentials.json".freeze
# The file token.yaml stores the user's access and refresh tokens, and is
# created automatically when the authorization flow completes for the first
# time.
TOKEN_PATH = "token.yaml".freeze
SCOPE = Google::Apis::SheetsV4::AUTH_SPREADSHEETS

# Ensure valid credentials, either by restoring from the saved credentials
# files or intitiating an OAuth2 authorization. If authorization is required,
# the user's default browser will be launched to approve the request.

# @return [Google::Auth::UserRefreshCredentials] OAuth2 credentials
def authorize
  client_id = Google::Auth::ClientId.from_file CREDENTIALS_PATH
  token_store = Google::Auth::Stores::FileTokenStore.new file: TOKEN_PATH
  authorizer = Google::Auth::UserAuthorizer.new client_id, SCOPE, token_store
  user_id = "default"
  credentials = authorizer.get_credentials user_id
  if credentials.nil?
    url = authorizer.get_authorization_url base_url: OOB_URI
    puts "Open the following URL in the browser and enter the " \
         "resulting code after authorization:\n" + url
    code = gets
    credentials = authorizer.get_and_store_credentials_from_code(
      user_id: user_id, code: code, base_url: OOB_URI
    )
  end
  credentials
end

# Initialize the API
service = Google::Apis::SheetsV4::SheetsService.new
service.client_options.application_name = APPLICATION_NAME
service.authorization = authorize

spreadsheet_id = '17bXAJELWjXIRmcJ-RPeg5_W4wszqZI3QxvE_ZIL3L6A'
range = 'rsvp'

class Api::RsvpsController < ApplicationController

  def create # append

    values = [
      'hi', 'hello'
    ]

    # TODO: Assign values to desired members of `request_body`:
    request_body = Google::Apis::SheetsV4::ValueRange.new(values: values)

    response = service.append_spreadsheet_value(spreadsheet_id, range, request_body)

    # TODO: Change code below to process the `response` object:
    puts response.to_json

  end

  def show

    # range = "Class Data!A2:E"
    # response = service.get_spreadsheet_values(spreadsheet_id, range)
    # puts "Name, Major:"
    # puts "No data found." if response.values.empty?
    # response.values.each do |row|
    #   # Print columns A and E, which correspond to indices 0 and 4.
    #   puts "#{row[0]}, #{row[4]}"
    # end

    range_names = [
      # Range names ...
    ]
    result = service.batch_get_spreadsheet_values(spreadsheet_id)
    # result = service.batch_get_spreadsheet_values(spreadsheet_id, ranges: range_names)
    puts "#{result.value_ranges.length} ranges retrieved."
  end

end

Here's how I set up my credentials in Google Cloud Console: