VS Code 1.99 no longer supports this OS, and for the last year has been popping up a warning about connecting to an unsupported OS.

If you can't downgrade to VS Code 1.98, you can follow Microsoft's instructions here to create a sysroot on your remote server containing glibc 2.28, which VS Code can use (in an unsupported mode).

If you did downgrade and it's still not working, try removing your ~/.vscode-server directory, to force it to redeploy the older server.