Duo API Failed Closed Error: API Request Failed

We are trying to implement DUO for our SSL VPN using Fortinet Firewall/Routers v 6.2.9 and we consistently receive the following error:

Traceback (most recent call last):
File “twisted\internet\defer.pyc”, line 654, in _runCallbacks

  File "twisted\internet\defer.pyc", line 1475, in gotResult
    
  File "twisted\internet\defer.pyc", line 1416, in _inlineCallbacks
    
  File "twisted\python\failure.pyc", line 512, in throwExceptionIntoGenerator
    
--- <exception caught here> ---
  File "duoauthproxy\lib\radius\duo_server.pyc", line 221, in duo_auth_only
    
  File "twisted\internet\defer.pyc", line 1416, in _inlineCallbacks
    
  File "twisted\python\failure.pyc", line 512, in throwExceptionIntoGenerator
    
  File "duoauthproxy\lib\duo_api\auth_client.pyc", line 115, in auth
    
  File "twisted\internet\defer.pyc", line 1416, in _inlineCallbacks
    
  File "twisted\python\failure.pyc", line 512, in throwExceptionIntoGenerator
    
  File "duoauthproxy\lib\duo_api\base_client.pyc", line 134, in call
    
  File "twisted\internet\defer.pyc", line 654, in _runCallbacks
    
  File "duoauthproxy\lib\duo_api\auth_client.pyc", line 63, in err_func
    
duoauthproxy.lib.duo_api.duo_api_errors.■■■■■■■■■■■■■■■■■■■■r: API Request Failed: Error([('SSL routines', 'ssl3_read_bytes', 'ssl handshake failure')])

Has anyone run across this before and know what is causing the issue? I’m not finding much using google.

Take a look at How do I resolve “Certificate verification failed” and “SSL handshake failure” errors when using the Duo Authentication Proxy?.

If you work through this article and still can’t resolve the issue, contact Duo Support.