When plugins fail validation in Logic Pro X, please open the "Plugin Manager" from within the Preferences menu and type in the associated plugin manufacturer (Slate Digital, Eiosis, D16 Group, Scuffham Amps, etc...) in the search box. Please ensure your iLok is plugged in securely.
Next, select the plugins that fail validation by holding the Command key (⌘) and clicking. Once the plugins are selected, click "Reset & Rescan Selection" and wait for the validation to complete. This could take several minutes.
Once validation is completed, open a plugin to verify it is working properly on your system.
If a plugin continues to fail validation, please ensure the iLok License Manager app is up-to-date on your system, and try "synchronizing" your iLok dongle. Your iLok dongle can be "synchronized" by right clicking on the iLok icon of the left of the manager, and clicking "synchronize". Note, you must be signed into the manager in order to do this. After the operation has completed, try rescanning the plugins within Logic Pro X once more.
If issues persist, please contact support here.