Your ROOT_URL in app.ini is https://src.whiteboxsystems.nl/ but you are visiting http://src.whiteboxsystems.nl/Whitebox/u-boot/src/commit/a800f2fda7a321cebe695e601bc8701fe9187fe9/configs/P1020MBG-PC_36BIT_defconfig
You should set ROOT_URL correctly, otherwise the web may not work correctly.