The focus contrast is presumably too low, at least if I assume that the yellow background color is the only focus highlighting and the link without focus has a white background. Then the contrast yellow to white is 1.13:1, but according to SC 1.4.11 at least 3:1 is necessary.
At Ensure that interactive elements are easy to identify there is an example for "Keyboard focus style".
The focus contrast is presumably too low, at least if I assume that the yellow background color is the only focus highlighting and the link without focus has a white background. Then the contrast yellow to white is 1.13:1, but according to SC 1.4.11 at least 3:1 is necessary.