Since upgrading to the new android version, "Nougat", Photoshop sketch just sits on the above message when trying to use the shapes tool.
Actually, I don't think it's the OS; it's more likely that it's the version of Sketch you're using. We've heard a number of reports similar to yours with the current version of the app.
I believe there's an update being released next week but if you want to there's also a beta version of Sketch for Android (v1.1.39) with some fixes that should help with the trouble you're having loading shapes.
You can get the beta by joining Adobe Android Apps - Google+ and following the instructions on this post: https://plus.google.com/101146399386092670308/posts/YJQDtMecX5X (you won't be able to see the post until you join the group).
Let me know how things go.