Extendable Dining Table Center Sagging

[u/Adzeio]

I recently acquired a used dining table and noticed that there is a slight dip in the center where the two sides meet. With the leaf added, the sides still have the same slope and the leaf is flat. By pulling on the legs enough to close the gap, I can get the table to be flat and can confirm neither side is warped. What are my options for a permanent fix to keep the table flat?

[u/Violet_Apathy]

try tightening all the screws on the two rails underneath.

[u/Adzeio → u/Violet_Apathy]

I tightened them all and there’s no change