Could not open mp3 encoding library

Using Mac OS High Sierra with Audacity 2.1.2. I am trying to export a file as an mp3 and get the following message:

So I downloaded and installed lame_64bit_osx.pkg and followed the instructions to install the libmp3lame64bit.dylib file.

I can see it in my Finder.

But then when I attempt to export a mp3 file I get:

I am following the instruction on the Installing LAME on Mac of the online help. But apparently I’m doing something wrong. Any ideas?

Go to Preferences > Libraries and make sure that the LAME library has been found.

Also, 2.1.2 is an old version. The current Audacity is 2.3.1, available here.