Selling Shares But not Enough Available

I am using Quicken 2017 on Windows 10. I am in a brokerage account and am trying to sell 119 shares when I have 417 shares of the security. When I try and save the transaction, Quicken tells me I'm trying to sell more than the # of shares I have and that I only have 47 shares available. The 119 shares were incorrectly assigned to a security of a similar name (same symbol though) as the correct security (3 letters different). The incorrect security holds only the sold shares (negative balance). Why is this?