I actually had do permissions reset on the remote folders as well..thanks anyway.

"public_html" and "\\public_html" are different paths.
Use a full path as you can see in GUI.
Also you should not use CreateDirectory to create multiple levels of folders in one call.

I can't understand, I've been using ftp and creating folders no problem, now I'm getting permissions denied with a new sftp connection. I'm using SshHostKeyFingerprint="ssh-rsa xxxx" to connect the session.
If I run session.ListDirectory("public_html") and I get list of folders + upload single files, but I get a permissions exception when I run session.CreateDirectory("\\public_html\\app\\code")
BUT If I use the WinSCP UI with the same connection credentials I can make a folder ….?
My WinScpNet version is 1.3.7.7601.