In this short tutorial I'm going to show you how to fix the browser error 503 error. It's super easy to fix, don't worry, just have a try.
1.Open Firefox browser, in the menu-bar, select Tools > Add-ons.
2.In the Add-ons window, hit the Plugins icon.
3.Locate and select the plug-ins you want to remove on the installed plug-ins list.
4.Click on the Disable button on the right side, the plug-in will not run after all steps above.
1.Click Stsrt up and type cmd.exe in the searchbox, then right click cmd.exe and select Run as administrator.
2.When a new window open, type scannow/sfc and press return, it will scan and fix any error on your computer.