E-Trade released their API recently and provided technical documentation which is somewhat useful but not complete.
Does anyone have a fully working example in C#
If you get "Due to a logon delay or other issue, your authentication could not be completed at this time. Please try again.",
then I think you put wrong keys in the authorize url.
You should follow the document by replacing the appropriate keys in this format
https://us.etrade.com/e/etws/authorize?key=&token=