Error message on web browser after parameter change

In some cases the user may see error messages in the web browser after a parameter change. The most common reasons are the following:  

 - the browser flash has not been cleared yet

 - another device had previously the same IP-address and its webpage was also checked by the same PC

 - the web browser is out of date

In the first two cases the solution is to clear the flash with Ctrl + F5 buttons. In the third case a browser update will likely solve the problem.