The Social Security Administration says it is investigating the root cause of website outages that have affected the “my Social Security” portal where recipients access their benefits. Notably, individuals who receive Supplemental Security Income have reported receiving a notice that said they were “not receiving benefits.” The agency said Tuesday that the notice is a mistake and is investigating how it happened. It is unclear how many people received the mistaken message. The website has crashed several times over the past few weeks as the agency conducts a major overhaul of operations to clamp down on what the White House and Elon Musk say is widespread fraud.