Hi Pratik,
not editing the database manually is the first thing i´ve learned in this case.
Now it works. I simply overlooked the option in theme options -> icon options. I only canceled the favicon from Appearance=> Customize => Site Identity=> Site Icons. I think i must have set it anytimes in both kategories. Sometimes it´s so easy.
Big thanks to you Pratik! Great support.
Tobi
PS: My site: http://www.appeart.com