How to solve the problem with CCTV video viewing in Firefox browser?

Firefox version 52 has changed the default settings for NPAPI plugins. This involves problems with displaying images (continuous prompts for installing plugins that have been already installed) from Ultimax and Hikvision cameras and DVRs/NVRs. It is possible to restore support for the plugins by setting the appropriate variable in Firefox options.
You should follow these steps:
1. In the address bar of the Firefox browser, enter the text: about:config and go to settings.
2. Right click anywhere in the window.
3. From the context menu choose New → Boolean
4. Enter the new setting as plugin.load_flash_only
5. Select the setting value as false
6. Close all browser windows and restart the browser.
The above method requires that communication between the device (source of the video) and the browser takes place via TCP packets (this is the default mode; if necessary it can be restored after entering menu → configuration → local).
It is not certain how long Firefox will allow such a workaround. It may happen that another Firefox update will block this method. Currently we recommend to use the IE browser. Manufacturers are working on newer ways to handle their devices with other browsers.