Hello there, @info648.
The setup for the peer-to-peer hosting method in QuickBooks Desktop requires you to enable it in every version you use. Thus, you'll need to set up again multi-user to make this feature work in your QuickBooks Enterprise Solutions version.
You may refer to the steps outlined in this article about how to enable multi-user so the computers on your network can access your company files using QuickBooks Enterprise: Set up and install a multi-user. You may start in Step 2 Set folder permissions since you already installed the new version.
For additional reference, you can use the following article for some video tutorials and tips while working with the product: Getting started with Enterprise.
Let me know if you have any other questions. I'll be happy to help you out. Have a great day ahead.