Blank website of webthings

I try to use an android tablet to access the webthings gateway, but I see a blank blue background (see the image below). The tablet is running Jellybean 4.2.
I tried to open the gateway in chrome app and in native browser app from the tablet with the same result, a blank blue screen.
Why is that and what can I do to see it correctly?

It can be closed.

Do tell the solution/issue… Inquiring minds and all.

You’re right.
It’s not about the gateway’s website but the tablet.
I needed to upgrade the Android system webview.