One of the features of the Sales manager is that most of the data can be entered directly by the user, instead of being downloaded from a web server. This allows the Sales Manager mobile app to be used in stand alone mode, without a web server. This is a popular option with single users, who are happy to enter all their data directly on the device, and who do not want the additional complication of a web server.
Because the Sales Manager is a multi-user system, some of the queries in the mobile app have to be run on the web server. For a stand-alone user, these queries will not return any results.
Please note that some features of the mobile app require in-app purchases. These are not included in the price of a subscription, and have to be bought separately. Without a server, backing up the database is particularly important. Users can save their databases to a Dropbox account, by purchasing the Backup Data option.