Cannot find module 'async'

The error message "Cannot find module 'async'" typically means that the module 'async' is not installed in your project or it is not in the correct path.

To resolve this issue, you can try the following steps:

1. Install the 'async' module using npm by running the following command in your terminal:

   npm install async

2. If you have already installed the 'async' module, make sure it is in the correct path and accessible to your project.

3. Check if there are any typos or misspellings in your code or file names.

4. Restart your server or development environment to ensure that any changes you made are reflected.

If these steps do not resolve the issue, please provide more details about your project and environment so that we can better assist you.