Mobile Font not showing up

HI all,

unfortunately we don't come to an end about trying to solve the font issue we experience on mobile devices. On desktop, everything looks great. But after activating humming bird the font is a times new roman on mobile devices. Is this caused by compressing some files? I also tried to exclude files from compressing, step by step, but didn't come to an end. Is there anything I can do about it? Thank you so much
Hubertus