Installation worked fine: Form doesn't load under Chrome or Edge

[GaryBartlett]

Hi,

I've installed SP Form Designer Free Trial on my SharePoint 365 site.

I am able to connect to it via the Forms Designer Client 3.1.5. on Windows 10 Professional, running .NET Framework 4.7.03056.

I designed and saved my form (following the Video 1 Tutorial precisely, AFAIK), via Chrome.

Chrome

1. On trying to view an existing item or add a new item, the spinning donut appears, seemingly indefinitely.
2. The same happens when I click on the Design Forms Button - a spinning donut.

Microsoft Edge

1. On trying to view an existing item or add a new item, the SharePoint page loads, but the form is invisible.
2. When I click the Design Forms] button I get an in browser [Yes] [No] question about running the Forms Designer app.

Firefox

1. The form works just fine under Firefox!
2. Clicking on the Design Forms button goes into a Working on it... loop for awhile, before presenting a page that says "Download the setup file, install it to your computer and run Forms Designer from Start menu."

Any advice? Do you think that it's worth uninstalling and reinstalling (a) on SharePoint and/or (b) on Windows?

Thanks very much.

Gary