You need to request an API Partnership to get your OAth credentials:

Make sure to request scope athlete:profile to be able to use OAuth for user login (default if setting SCOPE is omitted).

In development you should only use the sandbox services, which is the default unless you set USE_PRODUCTION to True.

    'trainingpeaks': {
        'SCOPE': ['athlete:profile'],
        'USE_PRODUCTION': False,

API documentation: