Ionic 2 PWA Sending email without plugin

I need your help about sending e-mail on ionic 2 PWA. I checked out this blog from nic raboy.
But when I post request to mailgun server I response a cors error with related mailgun server. It gives an error “ERROR Request header field Authorization is not allowed by Access-Control-Allow-Headers”
Then I realized that this issue is related mailgun api with javascript.
So İ guess that are there any other solution which is sending email on Ionic 2 as PWA (Progressive Web App) without Plugin ??

did you read the comments under the tutorial?

nic answers a question 9months ago

You cannot run it via a web browser, with Ionic Serve, or with Ionic View. I’m not positive if it will work with Ionic Live-Reload. All of these methods don’t truly install the application to the device or simulator. When the application is compiled and installed, it doesn’t operate on localhost and thus does not suffer from CORS related issues.

Does that clear things up?

So you need to run your pwa on a valid webserver to test the service.

It will not work with localhost

Yes I read the comments.but I had already deployed firebase and I get same issue when I debugging chrome

Ok I understand the issue… which is deployed on firebase already getting cors issue if you havent related with real domain on firebase and mailgun service.