It seems that something on your computer is cutting of the connection. As a workaround you could let somebody else create the branch so you only have to download it. And I would advise to raise a support ticket with the full stacktrace.
Did you install Tortoise on your machine and if so which version?
Regards,
Ronald
[EDIT] See the documentation here: https://docs.mendix.com/refguide/using-version-control-in-studio-pro#tortoisesvn-subclipse
This might indeed be a clue to the problem.