Sorry if I will not answer what you want to hear and if I might sound somewhat blunt.
This use-case diagram presents a detailed functional decomposition of your system. While the UML specs are neutral about this, all leading use-case authors strongly advise against functional decomposition, as this leads to complex diagrams that are very difficult to understand, and often imply some sequencing expressed with dependencies, which is ambiguous.
Use-cases should focus on actor goals or subgoals. If you want to describe the details of how these goals are addressed, you'd better go for an activity diagram.
By the way, about login see here.