Error building app on ionic pro but works fine on dev machine


My build is failing on ionic pro but using ionic serve works without problem.

It throws an error on the transpile of the typescript files saying it cannot find a module that is on the same folder that the file that imports it.

From the logs I have this:

[20:26:51] transpile started …
[20:26:54] typescript: src/models/PlaceSearchModel.ts, line: 1
Cannot find module ‘./Municipality’.

   L1:  import { Municipality } from './Municipality';

[20:26:54] ionic-app-script task: “build”
[20:26:54] Error: Failed to transpile program
Error: Failed to transpile program
at new BuildError (/usr/src/app/node_modules/@ionic/app-scripts/dist/util/errors.js:16:28)
at /usr/src/app/node_modules/@ionic/app-scripts/dist/transpile.js:137:20
at Promise ()
at transpileWorker (/usr/src/app/node_modules/@ionic/app-scripts/dist/transpile.js:103:12)
at Object.transpile (/usr/src/app/node_modules/@ionic/app-scripts/dist/transpile.js:61:12)
at buildProject (/usr/src/app/node_modules/@ionic/app-scripts/dist/build.js:97:78)
at /usr/src/app/node_modules/@ionic/app-scripts/dist/build.js:47:16

What is your local ionic info output?

cli packages: (C:\Users\RL\AppData\Roaming\npm\node_modules)

@ionic/cli-utils  : 1.19.0
ionic (Ionic CLI) : 3.19.0

global packages:

cordova (Cordova CLI) : 7.0.1

local packages:

@ionic/app-scripts : 2.1.4
Cordova Platforms  : android 6.2.3 browser 4.1.0 ios 4.4.0
Ionic Framework    : ionic-angular 3.6.0


Android SDK Tools : 26.0.2
Node              : v6.11.2
npm               : 3.10.10
OS                : Windows 10

Environment Variables:

ANDROID_HOME : C:\Users\RL\AppData\Local\Android\sdk


backend : pro