HTML disappearing

[Blue Billywig]

I've been using the w3schools editor to create an email signature in HTML. It seems to be working, however, when I send an email to Hotmail and forward it again, some HTML seems to be disappearing. The social icons at the bottom of the signature disappear. And I don't know whether it's something in the code that's causing this or whether that's something Hotmail does.

This is the code for the signature:  https://www.w3schools.com/code/tryit.asp?filename=GQ0Z9FFQQFQL