Sometimes there are order lines fail to validate as the system can not find the matched item code. If this happens, but if you know the item code they refre to you can still manually validate the order line.
Click on the line on INVALID status.
Double click on Matched Item Code cell. Click on the down arrow on right and that will pop up a drop down with all the item codes the system currently have.
Select the item code.
Now Click on Save.
Close the order re-open and make sure the item is saved. Now Select that line again, right click and select Mark As Valid.
Save the order. Now the line should be valid with a matched item code.
If you have multiple invalid lines this can be done for all the order lines.
Now you can process the order from the dashboard.