Dagenham & Redbridge have been relegated from League Two after losing at Leyton Orient, ending their nine-year stay in the Football League.
The Daggers, who reached League One in 2010, needed victory to keep their slim survival hopes alive.
Goals from Jamie Cureton and Clevid Dikamona gave them hope after Jay Simpson fired the O's into a 2-0 lead.
But Armand Gnanduillet fired in the winner to relegate Dagenham and keep Orient's play-off hopes alive.
Dagenham reached the Football League for the first time in their history in 2007, but they now return to the National League under John Still, the same manager who took the club from the Conference to League One.
The Daggers have League Two's worst goal difference, and have conceded 20 goals more this season than they had at this point last term.
Still's side have also struggled in attack, with 40-year-old striker Jamie Cureton netting nine goals, compared to the 20 he scored as Dagenham finished 14th in the 2014-15 campaign.
Boss Still, who returned for his third spell at the club in December, told BBC Radio London on Wednesday that he is committed to helping the Daggers gain promotion from the National League next season.