Norton antivirus is known for protecting various applications against viruses or malware attacks. It is installed to prevent any virus or malware entry into your system. Sometimes, Norton antivirus may stop, and it won’t work and showing Sonar failed to load error. It may be caused due to poor internet connectivity, weak server problem, outdated browsers and windows, etc. The best troubleshoot of Norton error 3039 is restarting your system and uninstalling and reinstalling the Norton antivirus p