Anti virus software cause internet connectivity issues
Antivirus don't effect on your internet connectivity. Antivirus is a program to keep you safe from the different types of Trojan, Malwares, Fraudtools and viruses etc. but sometimes makes mistakes when they try to get a solution to the virus traffic which was web traffic. So it gets slow down for a while to gather information which also an issue. They cause issue when they don't setup correctly. They also create issues when they conflict with some software or programs. If you have more than 1 antivirus on your system. Its also cause issues because of taking access to the internet. The lag is because of browsing and email scanning which is not noticeably slow down But fake anti virus can make all sorts of problemm for you.