"More than one remote source not supported" when copying files via pscp

Because you specify more than one remote source. username@server: . ← the dot here (which supposedly means your working directory) doesn't belong there. You cannot reference your working directory on another machine like this, and since there's a space between username@server and ., it'll be interpreted as two arguments.

Instead, specify an absolute path:

pscp C:\abc.php username@server:/home/user/foo

If you are using Windows path, chances are that you may have folders/directories with spaces in them, and these can cause that error as well. You may resolve this by using double quotes around your path. That was my problem

pscp -<arguments> username@server:/home/folder/file "C:\your windows path"