Bitly link doesn't work on another IP address

[ben18785]

I really like this package and I am trying to use it to live-share my screen with students. I do the following:

livecode::bitly_test_token()

which returns that all works. I then do:

livecode::serve_file(bitly = TRUE)

which returns:

Started sharing 'lecture_2_bare.Rmd' at ...
✖ The current ip address for the server is private, only users on the same local network are likely to be able to connect.
✔ Created bitlink 'https://bit.ly/3CJwsmG' for ...
Error: 'markdownExtensions' is not an exported object from 'namespace:markdown'

When I visit the bitly link from another machine, it just hangs and doesn't load the page. (It works fine from my own machine.)

Any ideas?