react js app keep showing "Getting Started" page after deploy

Question

I've just tried deploying my react js app with github pages. it works fine just a few seconds ago, then I edited a few text records in the database, then when I refreshed the page it suddenly changed into the "Getting Started with Create React App" page even though I haven't changed anything in the code.. why is that? how can I fix it?

this is the content of the .env file

...

#--------------------------------------------------------------------
# ENVIRONMENT
#--------------------------------------------------------------------

CI_ENVIRONMENT = development

#--------------------------------------------------------------------
# APP
#--------------------------------------------------------------------

 app.baseURL = 'https://myapp.example.com/'
# app.forceGlobalSecureRequests = false

...

#--------------------------------------------------------------------
# DATABASE
#--------------------------------------------------------------------

 database.default.hostname = localhost
 database.default.database = mydbname
 database.default.username = mydbusername
 database.default.password = mydbpassword
 database.default.DBDriver = MySQLi
# database.default.DBPrefix =
...

this is the content of package.json file:

{
  "homepage": "https://example01.github.io/project01",
  "name": "project01",
  ...
  "scripts": {
    "start": "react-scripts start",
    "predeploy": "npm run build",
    "deploy": "gh-pages -d build",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  ...
  "devDependencies": {
    "gh-pages": "^3.2.3"
  }
}