Your ROOT_URL in app.ini is https://src.whiteboxsystems.nl/ but you are visiting http://src.whiteboxsystems.nl/Whitebox/u-boot/src/commit/c35f8693942d8284c635592f263a0fe11abe1d1d/configs/lsxhl_defconfig
You should set ROOT_URL correctly, otherwise the web may not work correctly.