Unable to complete OAuth token

[tbenst]

The example for ATTSpeech.new does not work for me (see below). I am using a sandbox API key. Please let me know if I am missing something or if this is indeed a bug. Let me know how I can help diagnose the problem. Thanks!

ruby att_speech.rb
/Users/tyler/.rvm/gems/ruby-2.1.2/gems/att_speech-0.0.6/lib/att_speech/att_speech.rb:154:in rescue in get_tokens': Unable to complete oauth: (RuntimeError) from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/att_speech-0.0.6/lib/att_speech/att_speech.rb:137:inget_tokens'
from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/att_speech-0.0.6/lib/att_speech/att_speech.rb:51:in initialize' from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/calls.rb:25:inpublic_send'
from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/calls.rb:25:in dispatch' from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/calls.rb:67:indispatch'
from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/actor.rb:322:in block in handle_message' from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/actor.rb:416:inblock in task'
from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/tasks.rb:55:in block in initialize' from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/tasks/task_fiber.rb:13:inblock in create'
from (celluloid):0:in remote procedure call' from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/calls.rb:92:invalue'
from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/proxies/sync_proxy.rb:33:in method_missing' from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid/proxies/actor_proxy.rb:20:insend'
from /Users/tyler/.rvm/gems/ruby-2.1.2/gems/celluloid-0.15.2/lib/celluloid.rb:189:in new' from att_speech.rb:5:in

'