There are many reasons. The most popular is users are in different network groups.
A device that cannot be shared on a network is typically a standalone device that lacks network connectivity features, such as a basic calculator or a non-networked printer. These devices do not have the capability to communicate with other devices over a network and therefore cannot be accessed or utilized by multiple users simultaneously. In contrast, devices like networked printers or shared drives can be accessed by multiple users over a network.
Unplug the printer from the network.
After sharing the printer, add the users or groups that you want to have access to the printer, along with 'print' ability, such as 'create document' authority.
network printer
You have to give the printer the same SSID and password of the network your using.If you have a user password for the printer for multiple users then you would have to ask the administrator or whoever set the printer up for the password.
PG 213, 1) Network Discovery, 2) File and Printer Sharing
enter
If your printer is attached directly to your computer, you should share it (the way you do it depends of your operating system). If your printer is connected directly to your network (WiFi or Ethernet) it should be properly configured.
WIFI and ETHERNET
network
They usually need to be accessed by users who are outside of the internal network.