The Care Quality Commission (CQC) rated the trust as inadequate at providing a safe service and said it needed improving in three other areas.
It raised particular concerns over staff levels and the failure to ensure staff undertook basic training.
The trust said it was "disappointed" with the inadequate safety rating.
Dr Paul Lelliott, the deputy chief inspector of hospitals, said:  "Humber NHS Foundation Trust has a number of issues it has to address.
"They have been rated as inadequate for safety, and a great deal of what we saw demonstrates that the trust had not learnt all the lessons from our last comprehensive inspection [in 2014]."
The trust was, however, rated as good at providing a caring service.
Inspectors found that patients were "treated with kindness, dignity and respect" and staff were "committed and compassionate".
The inspection was carried out by the CQC between 11 and 15 April, but inspectors also made separate unannounced visits.
The report said the trust needed to ensure it trains all qualified staff in immediate life support and that all staff are trained in the use of seclusion.
The trust's chief executive David Hill said he welcomed the CQC's findings and was pleased the workforce's compassion and commitment had been recognised.
Regarding issues around patient safety, he said: "We would like to reassure people that this rating is in a small number of services and we have taken immediate action to address the issues."
The health watchdog has told Humber NHS Foundation Trust its mental health service provision is "unsafe" and "requires improvement".