The reason is that a non-8080 port is used. For the solution, please refer to: http://www.bkill.com/tech/201704/15709.html
The following is a snippet of the original text in case the original text is deleted:
Firefox browser prompts this address to access restricted solutions:
1. First, we use Firefox to open the restricted URL, and then remember the port number after the colon in the URL input box, as shown in the following figure:
2. Then we enter "about:config" in the URL input box and press Enter;
3. After that, in the pop-up "May lose the warranty" prompt box, click the "I promise to be careful" button;
4. Then right-click in the opened page, and then select "New → String" in the pop-up menu;
5. Then enter "network.security.ports.banned.override" in the pop-up window, and click the OK button, as shown in the following figure:
6. Finally, enter the value of the string. The value of the string is the port number we just wrote down, so here we enter 4045, and finally click OK to save and exit. After refreshing the page, you can find that the page can be opened normally.
