i cant get my pre written code back in workspace . and i open workspace says not authorized.

Everytime i try to open up Workspace for Java Basics Strings and Variables a message frome treehouse pops up saying Treehouse says not authorized . I had deleted the java introduction and class file by accident in the right tab of workspace and then posted a question on how to get it back. Someone suggested i copy the pre written code he gave me into a new file i created called java introductions but unfortunately i couldnt paste? Another person suggested that i delete workspace so i did that and now am in the position im in and a bit frustrated. Ive been stuck for two days now will appreciate any help thanks.