Plugin don’t re-activate after the last update!

I can’t reactivate Shield after the latest update, even if I delete the plugin and install it again I’m unable to activate it and use it. There’s no error code (even with the debug set to true) or message, the plugin just don’t activate.

Fortunately it’s a site that I still working on it, but would be terrible for a live site with people accessing all the time. :/