-907: Space for user session exhausted 

Explanation:

You have not been connected to the database system because there is not sufficient free temporary disk space to connect to a normal database session.

User Action:

...

       1.      You can connect as soon as another user has disconnected, or when deletion of other users’ result tables frees up sufficient storage space again.

       2.      You can use the Database Manager to connect and reconfigure the database instance.