Low mortgage rates continue to push borrowing costs lower this year, but not every consumer is able to qualify. About a quarter of mortgage refinance applications are getting denied, according to a study from LendingTree of more than 10 million mortgage applications.

The top four reasons why applications were denied were debt-to-income ratio, credit history, incomplete application, and insufficient collateral.

Debt-to-income ratios continue to be a harbinger for mortgage applicants. Those ratios accounted for 26% of mortgage denials and proved to be the biggest barrier for borrowers living in pricey cities. Applicants in San Jose, Calif.; Honolulu; Bridgeport, Conn.; San Francisco; and New York City saw refinance applications denied the most for this reason.

Credit history contributed to 24% of denials, according to LendingTree’s study. The highest share of applicants who failed to get approval due to credit history were in Winston-Salem, N.C.; Louisville, Ky.; McAllen, Texas; and Birmingham, Ala. The cities all have household incomes that are below the national median of $63,179.