When I try to activate the plugin I get fatal error: Cannot redeclare wise_chat_after_setup_theme_action()

When you try to activate Wise Chat Pro and you get the following error:

Fatal error: Cannot redeclare wise_chat_after_setup_theme_action() ….

It means that you also installed free Wise Chat plugin. Both free and Pro version cannot operate together. Please delete free Wise Chat first. Then please install and activate Wise Chat Pro.