Notice: Trying to get property of non-object in DrupalOAuthDataStore->lookup_nonce()

I try to create the following configuration:

authtest.mydomain.com
- Oauth 6.x-3.0-beta3
- Oauth Provider UI 6.x-3.0-beta3
- Oauth Login Provider 6.x-1.0
- Services 6.x-3.0-beta2
- Rest Server 6.x-3.0-beta2

Log entry:
Notice: Trying to get property of non-object in DrupalOAuthDataStore->lookup_nonce() (line 85 of /var/aegir/platforms/pressflow-6.20-dev/sites/all/modules/oauth/includes/DrupalOAuthDataStore.inc).

consumer.mydomain.com
- Oauth 6.x-3.0-beta3
- Oauth Consumer UI 6.x-3.0-beta3
- Oauth Connector 6.x-1.0-alpha1

Log entry:
Exception: Failed to fetch data from url "http://authtest.mydomain.com/oauth/request_token" (HTTP response code 401 Unauthorized): in DrupalOAuthClient->get() (line 351 of /var/aegir/platforms/pressflow-6.20-dev/sites/all/modules/oauth/includes/DrupalOAuthClient.inc).

consumer configuration:
name: authtest
title: authtest
Base URL: http://authtest.mydomain.com
UseriD:
Ressource: http://authtest.mydomain.com/oauthlogin/api/user/info
field: uid

Name:
Ressource: http://authtest.mydomain.com/oauthlogin/api/user/info
field: name

Avatar: http://authtest.mydomain.com/oauthlogin/api/user/info
field: avatar

If i want to login from consumer.mydomain.com, i receive the following message in the GUI (blank page without drupal theme):
The website encountered an unexpected error. Please try again later.

It's the same message if i try manually to open the url: http://authtest.mydomain.com/oauth/request_token