Your ROOT_URL in app.ini is https://src.whiteboxsystems.nl/ but you are visiting http://src.whiteboxsystems.nl/Whitebox/u-boot/blame/commit/96368e6e389e6be64b9f4dfa654d5fdcf2d32653/configs/k2hk_evm_defconfig
You should set ROOT_URL correctly, otherwise the web may not work correctly.