Icons and social media icons showing up as squares

Hey!
On my site for example on this page https://cararegroup.com/carare-group-contact/
All the icons both icons on the page and social media icons in the header/footer show up as squares when using chrome and Safari. On Firefox, they show up as they should.

Can you help me how to fix this, the icons should ofcourse be visible regardless of the browser? I have tried to write in the icons as code, but that does not help.

Thanks.

Ticket