The code below " Add the following within the
head element:" is truncated after “…device width,”
In my browser there is a scrollbar, you should be able to select it all and copy&paste it.
If you can’t please try without browser extensions.
If that doesn’t solve it, please see what your user agent is at this link: https://www.whatismybrowser.com/detect/what-is-my-user-agent/
and paste it in an answer post