Hummingbird Problems with CSS, Customizer and checking enqueued files.

Hi, I have multiple problems with Hummingbird on my website. Hummingbird is already scanning and "CHECKING ENQUEUED FILES" for a couple of hours. Moreover, I installed it yesterday and it worked fine. However, today, I noticed that I cannot change any settings in customizer (e.g. I changed the footer colors and sizes, pressed save, it saved, I closed customizer and no change happened - it looked like before - only the text size was affected, but not the color). It seems like it prevents those changes because when I disabled Hummingbird the footer color had changed. In the moment when I enabled it again, the color switched back to the old setup.
So I switched Hummingbird off again, but that time it totally screwed my CSS design, so I had to switch it on again to get my CSS design back.
So what do I need to do to make Hummingbird work properly? Can you help me? Thanks in advance! (I granted you access so you can take a look yourselves and maybe fix it.) Much appreciated.