Router 1 is configured with static NAT. Addressing on the router and the web server are correctly configured, but there is no connectivity between the web server and user on the Internet. What is a possible reason for the lack of connectivity

The router NAT configuration has an incorrect inside local address.

Explanation:

The term Inside in a Network Address Translation (NAT) context refers to networks owned by an organisation that must be translated. When NAT is configured, hosts within this network have addresses in one space (known as the local address space). These hosts appear to those users outside the network as being in another space (known as the global address space).

The term Outside refers to those networks to which the stub network connects, and which are not under the control of an organisation. Also, hosts in outside networks can be subject to translation, and can thus have local and global addresses