An autoblock is a form of automatic blocking, especially on a computer network, inhibiting the use of a feature or website.
In Mount and Blade: Warband, the "autoblock" feature is not present in the same way it is in some other games. Players must manually block incoming attacks by timing their movements and using the block key. However, there are community mods that may implement similar features or enhance combat mechanics. In Native Warband, effective blocking relies on player skill and awareness rather than automatic functions.
This can be due to multiple reasons. One would be you may have misspelled the email address you were trying to contact. A second would be the email account does not exist or has been suspended by the provider. A third reason could be that they may have added you to some autoblock list or reject filter.