I've added my Bitbucket-Account to SourceTree, generated a SSH key-pair during this step and registered the key on the Web.

Cloning, push/pull everything works fine.

After reboot it seems like the key-pair doesn't work anymore (Make sure you have correct access rights and the repository exists).
With ssh-add -L the key isn't listed (before reboot it was).

My config is attached in a screenshot. The Host "Suizi11-Bitbucket" is never used, because the log while e.g. pulling says it will try my default key (id_rsa). So the last Host "*" is used probably.
The Account "Suizi11_Kreisel" only works, because I've renamed the host from Suizi11_Kreisel to bitbucket.org.

Why the original generated Hosts are not used? I think this is a bug.