Pip.install has stopped working: “Could not find a version that satisfies the requirement “

I have seen a few related questions, and I've tried all of their recommendations:

• I'm using anaconda, so I downgraded from 3.7 to 3.6
• I upgraded pip using curl https://bootstrap.pypa.io/get-pip.py | sudo python
• I installed the latest version of openssl (1.1.1)
• I updated all Anaconda libraries
• I am connected to the Internet (obviously, since I'm posting here) and not behind a firewall.

And yet, every time I run "pip install " or "pip install ==" I get the following error:

ERROR: Could not find a version that satisfies the requirement (from versions: none)
ERROR: No matching distribution found for

I'm on a Mac, Mojave v10.14.4

I recently installed prodigy.ai, which seemed to replace a bunch of packages with (perhaps) older versions, but I still cannot figure out how to fix this issue. The one thing I haven't tried is uninstalling Anaconda and reinstalling it.

Thanks for any help on this.