Possible reason: When there is an important update to iSlide, we will mandatorily ask users to update, otherwise you will not be able to log in, buy and get online resources and more.
Please update your iSlide add-in to the latest version. You can download the installation package by clicking "About" button or on our official website.
Method ONE: Update directly via the "About" button in the add-in
Method TWO: Download the latest version of the installation package on our official website: https://en.islide.cc/download