Issue with custom app

Account ID - 379048
Account Name - intercroma-4dcbbf5fdb03046.freshsales.io

App Information:

App ID Cotação: Freshworks
App ID Calculadora de Preços: Freshworks

App Name:

  1. Quotation
  2. Price Calculator

App Type - (Custom/Public/External) Custom
Region - useast1-pod1
Organization URL - intercroma.myfreshworks.com
Portal URL - intercroma-4dcbbf5fdb03046.freshsales.io

Description:
The customer has build a custom app where the Custom app shows blank screen when clicked on.

However, the custom app details that are related to the contacts are seen in the contact landing page when ?dev=true is added to the URL of the contact.

Custom app description:

The custom app work as two calculators, one for prices and one for quotation. Both connect with product modules and some custom modules

This is an image of the quote calculator from a few months ago.

The price calculator receives some parameters, such as product name, profit margin, shipping, amount for discount and registers this via API within a customized module. And the quote calculator assembles a PDF and a sales opportunity according to the data previously registered in the price calculator.

Trouble-shooting steps suggested:

Disintegrated the custom app, and re-integrated the same, issue still persists

Relevant screenshots:

Error code upon clicking the Custom app:

Failed status when clicking on the custom app:

?dev=true added to the contact URL:

Custom app details in the contact landing page: