When plugins fail validation in Logic Pro X, please open the "Plugin Manager" from within the Preferences menu and type in the plugin name in the search box. If using an iLok dongle, 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 you have an ARM based Mac (M1), please see the following article: Apple ARM Support M1 Processors
If your plugin does show in the Logic plugin manager as "Successfully validated" but still doesn't show up in Logic, close Logic and then open the Slate Audio Center application. Once logged in, go to your settings and under the "Misc" tab, hit "Clear Logic Pro Cache".
If issues persist, please contact support here.