When installing a render/processing software in a different path than default, you may have to configure its Deadline Plugin executable path to Deadline will be able to find it.
To setup the executable path for a Deadline Plugin:
Make sure you are using the Deadline Monitor in Super User Mode:
Go to Tools > Configure Plugins:
In the plugin list on the left, select the plugin you want to configure,
And in the Plugin Executable text box (in this case Blender), type in a new path, or click the browse button to set the path.
* Multiple alternative paths can be set separated by lines.