ERR_SSL_PROTOCOL_ERROR

How do I resolve this issue. I am unable to access my gmail or yahoo mail accounts since purchasing and installing Sophos on mi IMac. I jhave a chromebook that does not need the internet. It goes stright to the cloud and works perfect. I have tried every suggestion from many sights to resolve the issue. I am sure it has something to do with your software. I have been unable to rid my system of the sophos application and have tried trashing the application, unsubscribing from the application, deleting the application and it continues to return. Everytime I log into my computer I go to the list of applications and it continues to appear. HELP!!