Why is my license key is invalid?

Note: The KingSumo WordPress plugin has been retired and no longer receives updates. It keeps working, and you can still download the last version (1.8.10) at kingsumo.com/latest. For new giveaways, we recommend the KingSumo web app.

It is very likely that this is because you have an old plugin version of KingSumo. Make sure you upgrade to the latest version of the plugin here: kingsumo.com/latest