If it has been Social Security disability benefits that have been denied, then you can know the reason for the denial by reading the denial notice. Your attorney can help explain it. Social Security disability requires that a claimant have "insured status," meaning 40 covered quarters with 20 earned within the 40 calendar quarters immediately preceding disability onset, and an impairment so severe that work at any kind of job is precluded. Your medical providers do not have the authority to decide if you are disabled, and the opinion of a nurse practitioner may not be acceptable medical opinion. Your attorney should be aggressively developing and presenting your evidence.
Best wishes for a favorable outcome, and please remember to designate a best answer.
This answer is offered as a public service for general information only and may not be relied upon as legal advice.