Deadline 10.4 error: "No module named 'Deadline.Plugins.DeadlinePlugin'; 'Deadline.Plugins' is not a package"

This error suggests that there's an issue with the Python environment configuration for your Deadline 10.4 installation. The error "No module named 'Deadline.Plugins.DeadlinePlugin'" indicates that Python cannot find the necessary Deadline modules.

For Deadline Cloud, you need to ensure that both the worker agent and the appropriate adaptors are properly installed. Here are some steps to troubleshoot:

1. Make sure you've installed the Deadline Cloud worker agent correctly:

• On Linux: /opt/deadline/worker/bin/python -m pip install deadline-cloud-worker-agent
• On Windows: python -m pip install deadline-cloud-worker-agent

2. Install the necessary Deadline Cloud adaptors for your DCC applications:

pip install deadline deadline-cloud-for-maya deadline-cloud-for-nuke deadline-cloud-for-blender deadline-cloud-for-3ds-max

3. Verify that the executable programs are available on the system search path (PATH environment variable).

4. For Linux, check that the PATH is properly set in the user's .bashrc or .bash_profile, or in system configuration files.

5. For Windows, verify the PATH in user-specific or system-wide environment variables.

Since you're using Deadline 10.4 specifically, make sure you have the latest version (10.4.1 is now available) which includes support for managing Deadline Cloud Usage-Based Licensing alongside floating licenses and compatibility with newer versions of various DCC applications.

If you're still experiencing issues, you might need to check if the Python interpreter being used by Deadline has access to the correct paths where the Deadline modules are installed.
Sources
Worker host setup and configuration - Deadline Cloud
Thinkbox Deadline 10.4.1 release - AWS
Install and configure software required for jobs - Deadline Cloud