Why am I receiving this error?
The error is displaying due to attempting to adjust your inventory by a number that will still continue to show as negative.
In the example below, the current inventory is -934. By selecting "Increase Inventory" by +41, the end result will still be a negative number (-893).
How can I fix it?
You will need to adjust your inventory by adding a number that will no longer be negative (below zero).
In the example, we originally wanted to have 41 as our inventory. We would need to add 975 to equal that number and no longer be negative.