Ionic Pro: Connecting existing app

Hi,
I’M using latest IONIC v.3.7.1.

Generating a new Ionic app for Ionic Pro from scratch works fine.
However I would like to connect an existing IONIC2 app I have used with the legacy Ionic View.
Now I want to connect it to IONIC Pro. So I set up the following way.
ionic link
git add *
git commit -a -m "Initial commit"
git push ionic master

When I go to the Ionic Pro dashboard and click the app I always see a build failed message unter logs:
Any help is appreciated!

Running with gitlab-ci-multi-runner 9.1.0 (0118d89) on Prod Snapshot Builds 1 (c9648220) Using Shell executor... Running on ip-10-2-92-21... Cloning repository... Cloning into '/home/gitlab-runner/builds/c9648220/0/project-1'... Checking out 845012a5 as master... Skipping Git submodules setup $ fetch-updates Checking for build process updates... $ build-app Fetching build dependencies... Running: npm install npm WARN deprecated object-keys@0.2.0: Please update to the latest object-keys > node-sass@4.5.3 install /usr/src/app/node_modules/node-sass > node scripts/install.js Downloading binary from https://github.com/sass/node-sass/releases/download/v4.5.3/linux-x64-57_binding.node Download complete Binary saved to /usr/src/app/node_modules/node-sass/vendor/linux-x64-57/binding.node Caching binary to /home/gitlab-runner/.npm/node-sass/4.5.3/linux-x64-57_binding.node > uglifyjs-webpack-plugin@0.4.6 postinstall /usr/src/app/node_modules/uglifyjs-webpack-plugin > node lib/post_install.js > node-sass@4.5.3 postinstall /usr/src/app/node_modules/node-sass > node scripts/build.js Binary found at /usr/src/app/node_modules/node-sass/vendor/linux-x64-57/binding.node Testing binary Binary is fine npm WARN @ionic-native/battery-status@4.3.0 requires a peer of @ionic-native/core@^4.2.0 but none was installed. npm WARN @ionic-native/ble@4.3.0 requires a peer of @ionic-native/core@^4.2.0 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/common@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/compiler@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/compiler-cli@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/core@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/forms@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/http@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/platform-browser@4.4.3 but none was installed. npm WARN ionic-angular@3.7.1 requires a peer of @angular/platform-browser-dynamic@4.4.3 but none was installed. npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.1.2 (node_modules/fsevents): npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.1.2: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"}) added 768 packages in 25.82s npm install succeeded Running: npm run build npm info it worked if it ends with ok npm info using npm@5.3.0 npm info using node@v8.2.1 npm info lifecycle ionic-hello-world@0.0.0~prebuild: ionic-hello-world@0.0.0 npm info lifecycle ionic-hello-world@0.0.0~build: ionic-hello-world@0.0.0 > ionic-hello-world@0.0.0 build /usr/src/app > ionic-app-scripts build [10:16:03] ionic-app-scripts 3.0.0 [10:16:03] build dev started ... [10:16:03] clean started ... [10:16:03] clean finished in 1 ms [10:16:03] copy started ... [10:16:03] deeplinks started ... [10:16:03] deeplinks finished in 74 ms [10:16:03] transpile started ... [10:16:06] typescript: src/pages/myhome/myhome.ts, line: 56 Property 'interval' does not exist on type 'typeof Observable'. L55: this.timer = Observable.interval(BLE_UPDATE_IV); L56: this.timer.subscribe( L57: (data) => { [10:16:06] ionic-app-script task: "build" [10:16:06] 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:159:20 at Promise ()
    at transpileWorker (/usr/src/app/node_modules/@ionic/app-scripts/dist/transpile.js:107:12)
    at Object.transpile (/usr/src/app/node_modules/@ionic/app-scripts/dist/transpile.js:64:12)
    at /usr/src/app/node_modules/@ionic/app-scripts/dist/build.js:106:82
    at 
npm info lifecycle ionic-hello-world@0.0.0~build: Failed to exec build script
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! ionic-hello-world@0.0.0 build: `ionic-app-scripts build`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the ionic-hello-world@0.0.0 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/gitlab-runner/.npm/_logs/2017-10-03T10_16_06_221Z-debug.log
npm run build failed
Make sure your project has a build script in the package.json
Running after script...
$ clean-up
Cleaning up files...
Successful clean up
ERROR: Job failed: exit status 1

Ionic Pro is a hosted and closed source service, so there is not much we, the community, can help you with, sorry. Check these:

You can - and should - contact support at http://ionicframework.com/support#support

When I migrated over to Pro I ended up creating a brand new project and made sure at least that would build.

Then I added the plugins one by one, made sure it still built, then moved the source.