As I am new to appian env, I tried to access the workspace for hands-on practice. For the same I request an instance to communityedition@appian.com and I got credentials to logged in this environment. After logged in it is rendering "403 Access Denied" and You don't have permission to view this page.
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I have faced same issue basically for this you have to mail to appian support only they can resolve this issue from their side.