Login Form Issues With Deployed Vaadin App


I have been trying to build a simple application with Vaadin as a study project. I got it to a point where it had some basic login functionality and debit / credit functionality (it is meant to be a home accounts software). I have deployed this on Redhats PAAS offering
and I am now seeing a problem that I did not come across when running locally.

The landing screen has just a LoginForm. When I enter a valid username and password, nothing happens on Chrome. If I try on Firefox I am logged into the application, however I get the below warning dialog before the login occurs.

Although this page is encrypted, the information you have entered is to be sent over an unencrypted connection and could easily be read by a third party.
Are you sure you want to continue sending this information?

The problem in Chrome only arises when I try and use the login functionality. There is also a
create user
link on the home page which will make a call and receive a response from the backend which works in both Chrome and Firefox.

My question is, why would this message be shown on Firefox and why would Chrome not give the option to continue as Firefox does?

Do I need to specifically make some setting in Vaadin to specify to use https?

Any help appreciated.

The url for the app is:

You can see the misbehaving functionality by attempting to login with the below on Chrome, and the warning on FF