Check the clip alignment. If the panels are fabric covered, check that allowance has been made for the correct thickness of the fabric on the edge of the panels, and check that the 10mm (3/8″) drill hole is square to face.
For USA Customers
Architectural customers in the US such as architects and general & specialty contractors are welcome to buy Fastmount online at https://shop.fastmount.com.
Marine and furniture customers in the US can continue to purchase through Spradling and Sugatsune.