The easiest way to register and license plugins is by using the aescripts + aeplugins manager app. You can download it here.

IMPORTANT: Always make sure you are using the latest version of the plugin which you can install using the manager app or by downloading it from 'My Downloads & Licenses'. If you are seeing a watermark (cross lines, red x, colored dots, etc) it means that the plugin is not yet licensed. Please follow these simple instructions to enter your license code and license the plugin to remove the watermark.

The manager app is as simple as clicking activate and restarting your host application. If you are prompted to enter your license code every time please use the manager app please run the licensing troubleshooter as explained here.

Manual Licensing Method

If you prefer to license your plugin manually, you can find your serial key here and register it inside After Effects:

Adobe Media Encoder

If using Adobe Media Encoder (AME), make sure the plugin is licensed in After Effects (or Premiere Pro) first by confirming there is no more watermark. Then restart AME.

If the watermark persists, try the following steps in order:

• Purge all memory & disk cache: Edit → Purge → All Memory & Disk Cache:
  
• Restart all host applications (including Adobe Media Encoder if used)

If you received an error with your license key, try the following steps in order:

• Ensure there are no spaces before or after when entering your license.
• Ensure there's no formatting applied to your license after copying it. You can do this by pasting it into a browser search bar; this removes the formatting and now you can copy/paste it back into After Effects. 
• For more error codes, check this more extensive list

If you reached your maximum number of activations

You can reset all licenses by doing the following steps:

1. Go to My Downloads & Licenses (login if required)
2. Click info on the product you want to reset the licenses for:
   
   
3. Deactivate all previous activations:
   
4. Re-register the plugin on your current machine, either manually or via the manager app
5. Restart the host application

If you have any issues just let us know and we will assist. If you receive an error message, please post a screenshot so we can diagnose the cause.