A private school that was rated inadequate last year has still not made sufficient progress, Ofsted inspectors said.
They found pupils at Progress School in Thrapston, Northamptonshire "did not have meaningful opportunities to learn".
The regulator also said that lessons "contributed weakly to their learning".
The school has capacity for 60 children aged 11-16, but 27 were on its roll when Ofsted visited in April.
The school offers education to pupils with behavioural, social, emotional and mental health needs, and many of these pupils had been excluded from their previous schools.
Ofsted found pupils at the school, whose annual fees range between £14,500 and £32,500, were "not able to recall their learning" and "did not develop skills as well as they could".
