Ubuntu PPA problem

[constable]

Code:

E: The repository 'ppa.launchpad.net/ppsspp/stable/ubuntu xenial Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

Edited the above repo url to remove http to get past the link filter on posting.