Cost of project always zero although many transactions assigned to it in QB Online

Thanks for posting in the Community, @jamalq2006.
 

Let me help you fix this and provide you with some information about costs reflecting zero in projects. There are situations like this when the system encounters browser-related issues. It might be caused by a corrupted file cache stored in your browser. That's why your costs in a project reflect zero.
 

We can do some troubleshooting steps to rule this out by using an incognito window.
 

Here are the shortcut keys:
 

• Google Chrome: press Ctrl + Shift + N
• Mozilla Firefox: press Ctrl + Shift + P
• Safari (new versions): press Command + Shift + N
   

If this works, you need to clear the browser's cache to restart the system.
 

Also, the allocated cost in the project will reflect zero when you create a purchase order (PO) because it's a non-posting transaction. It doesn't directly affect the project cost. 
I would appreciate it if you'd provide information on what type of transaction you created. 
 

If you created a PO, you need to convert it first into a bill for the cost to appear.
 

Here's an article that can guide you on how to convert your PO into a bill: Add purchase orders to expenses, bills, or checks in QuickBooks Online.

If you have further concerns with projects, click the reply button below. I'd be around to help. Have a nice day!