OpenID provider "simpleid": authentication not possible

[DrVanScott]

I would like to use barkeep within our company. Unfortunately, i can't use external openid providers - such as google - due to our proxy (with authentication). I found no way to have barkeep using our proxy. So i decided to set up an own, internal openid provider: simpleid ( http://simpleid.koinic.net/ ). Unfortunately i can't get it to work:

At first, everything seems fine: The first request on barkeep redirects to the login page of simpleid. After i entered my credentials, i get redirected back to barkeep, but then barkeep deny access with

"Sorry, we could not authenticate you with this identifier."

On the openid-provider side, the authentication fails due to

"simpleid_verify_signatures: Attempting to verify an association with a shared key."

My knowledge about openid is near to zero. Maybe someone can help me?