Go to Backend > Settings > License info, and just hit the save button on that page. It will validate your license once again and remove the error message.
Go to Backend > Settings > License info, and just hit the save button on that page. It will validate your license once again and remove the error message.
We offered quite some time for upgrading to latest 1.x and 2.x branches, we did another extensions a few months ago, then another one a few weeks ago. We can't really keep up supporting 1.x, this is why you'll have to upgrade to latest 1.x(which will fix your above issue) then to 2.x, otherwise, we can't really help.
1.9.9 is almost 4 years old.