This is a very important topic because if you enter a variation incorrectly, Sku Grid will put the item out of stock since the variation you entered does not exist. 

Once you're logged into Sku Grid, you're automatically placed on the My Items page. If you're already logged in, just click on My Items to be redirected to your grid. 

In the 2nd set of Filters on the page, select Incorrect Variation Name from the drop down menu. Sku Grid will filter and display all items where it is very likely that the variation has been entered incorrectly.

Under the variation names that you've entered you will see a link that says Show All.  Click the Show All link. 

This will display a list in a drop down menu containing all possible variations as they would need to be entered into Sku Grid.

If what you typed is not in the drop down menu exactly as shown, you need to edit the item in the grid and correct the variation name as it was just displayed to you. Make any necessary corrections and then click Update. That will save your changes. Once the item's variation has been confirmed to be correct, you can click on Force Reprice to force reprice the item.