Heroku Error: Cannot find module './app/firebase-namespace'

Question

I'm trying to deploy my app on Heroku, but I found this error with firebase:

2022-01-08T19:03:43.936831+00:00 app[web.1]: 
2022-01-08T19:03:43.936832+00:00 app[web.1]: Error: Cannot find module './app/firebase-namespace'
2022-01-08T19:03:43.936832+00:00 app[web.1]: Require stack:
2022-01-08T19:03:43.936833+00:00 app[web.1]: - /app/node_modules/firebase-admin/lib/default-namespace.js
2022-01-08T19:03:43.936833+00:00 app[web.1]: - /app/node_modules/firebase-admin/lib/index.js
2022-01-08T19:03:43.936834+00:00 app[web.1]: - /app/rutas/modelo/firebase.js
2022-01-08T19:03:43.936834+00:00 app[web.1]: - /app/rutas/test.js
2022-01-08T19:03:43.936834+00:00 app[web.1]: - /app/rutas/index.js
2022-01-08T19:03:43.936835+00:00 app[web.1]: - /app/app.js
2022-01-08T19:03:43.936835+00:00 app[web.1]: at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
2022-01-08T19:03:43.936835+00:00 app[web.1]: at Function.Module._load (node:internal/modules/cjs/loader:778:27)
2022-01-08T19:03:43.936836+00:00 app[web.1]: at Module.require (node:internal/modules/cjs/loader:1005:19)
2022-01-08T19:03:43.936836+00:00 app[web.1]: at require (node:internal/modules/cjs/helpers:102:18)
2022-01-08T19:03:43.936836+00:00 app[web.1]: at Object.<anonymous> (/app/node_modules/firebase-admin/lib/default-namespace.js:19:28)
2022-01-08T19:03:43.936837+00:00 app[web.1]: at Module._compile (node:internal/modules/cjs/loader:1101:14)
2022-01-08T19:03:43.936837+00:00 app[web.1]: at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
2022-01-08T19:03:43.936837+00:00 app[web.1]: at Module.load (node:internal/modules/cjs/loader:981:32)
2022-01-08T19:03:43.936838+00:00 app[web.1]: at Function.Module._load (node:internal/modules/cjs/loader:822:12)
2022-01-08T19:03:43.936838+00:00 app[web.1]: at Module.require (node:internal/modules/cjs/loader:1005:19) {
2022-01-08T19:03:43.936838+00:00 app[web.1]: code: 'MODULE_NOT_FOUND',

This is my package.json file:

"dependencies": {
"cookie-parser": "^1.4.6",
"cors": "^2.8.5",
"express": "^4.17.2",
"express-handlebars": "^5.3.5",
"express-rate-limit": "^5.5.1",
"express-session": "^1.17.1",
"firebase-admin": "^10.0.1",
"handlebars": "^4.7.7",
"i18n": "^0.13.4",
"jsonwebtoken": "^8.5.1",
"request": "^2.88.2"   },

The app is running correctly locally, but deploying to Heroku crashed. I also checked that this dependencies are in Heroku server.

Node is version 16.13.1