Error in tolower(iface): invalid multibyte string 4

[kolorado]

I followed the installation steps described here:

But when I write s <- livecode::serve_file() I get the following error:

Error in tolower(iface) : invalid multibyte string 4

I checked my IP addresses as explained in this issue, but it does not seem to contain any non-ascii characters. I'm not sure what's wrong.