This question has been answered by BobRay. See the first response.
You can log back in after an hour if the settings are default. Or you can just uncheck blocked from the user.
Do you have access to the Database?
You can go to the modx_user_attributes table and look for your full name, then set the 'blocked' field to 0 and the other two "blocked entries to empty.
Delete all files in the core/cache directory (but not the directory itself) before logging in.