Your ROOT_URL in app.ini is https://src.whiteboxsystems.nl/ but you are visiting http://src.whiteboxsystems.nl/Whitebox/u-boot/blame/commit/adad96e60d0eb1bbc4d0b96c89decf385a426e42/configs/M5235EVB_Flash32_defconfig
You should set ROOT_URL correctly, otherwise the web may not work correctly.