Welcome to the QuickBooks Community. It's great to learn you're using QuickBooks to help manage your income and expenses. Don't worry, I'll be happy to point you in the right direction from here.
Normally, when you receive a pop-up warning in QuickBooks, a reason to why the funds can't be withdrawn also appears. In case you aren't seeing an direction or reasoning to why the warning is appearing, I recommend getting in touch with our support team so they can share your screen and have a visual reference to what you're seeing. This helps the specialist get to a resolution in a timely manner. Here are our contact details:
Schedule a Callback or start a Chat: click(?) in the upper right in QuickBooks Online > enter "Contact support" > choose Contact Us > provide a brief summary > select Let's Talk > choose Get a callbackor Start a Chat.