Visual Studio remote debugging (ssh) on linux OS (buildroot)?

I'm trying to attach Visual Studio 2019 to a linux machine (64-bit Intel) running a custom Buildroot OS. When I try to connect via ssh with a password I get the error:

"Unable to connect to the Microsoft Visual Studio Remote Debugger named user@ip.address. Operation not supported. Unknown error: 0x80004005."

This is what happens right after I enter my credentials in the Attach to Process screen. That is before I even see the list of processes to attach to.

If I point VS to a different Linux machine (Ubuntu) it immediately shows me a list of processes running on it.

Any idea what I'm missing? Buildroot's sshd server says: OpenSSH_7.5p1, OpenSSL 1.0.2k 26 Jan 2017 and I do have wget installed. I installed curl in case that was it, but it still didn't work.

My Buildroot system is not on the public internet, but I'm not sure that matters. I'm guessing/hoping there's a secret requirement that I'm missing and can't find via google. Anyone have any ideas to try?