When blocking the cash register, the NAV server sends an “electronic message” to the cash register, as a result of which the cash register is placed in a blocked state. When blocked, the cash register is not suitable for operational use, so no receipt can be issued with it. What are the situations in which NAV may block a cash register? In what cases the NAV blocks the cash register, it is determined by law. One such case is when the service providing an online data connection to the cash register is paused or restricted. More details are as follows.
Source: fiscal-requirements.com
