У вашего броузера проблема в совместимости с HTML5
----Only IF its still not working----
12/03/2017 : Updated Description (Details are mentioned here since last time and have been explained below)
I have seen a few Youtube channel owners finding the twitter icon symbol crashing after posting it on your cover art.
This is a very easy fix if you go to see not much complexity to it.
Step 1: As shown above add the www prefix.
Step 2: Don't forget to change the http to https.
[[
Step 3(rare cases): Add the slash at the end.
So the new URL should look like this:
https://www.twitter.com/d3adkid/ -- Add this ending slash
]]
P.S: ONLY ADD THE SLASH IF IT DOES NOT WORK AS SHOWN IN THE VIDEO.