The English Football League has asked Derby's administrators for an "urgent update" on how the club will be funded for the rest of the season.
On 27 January the EFL and the Championship club's administrators, Quantuma, agreed a four-week extension to the deadline to provide proof of funding.
The EFL has now stated that it has still not received this evidence, nor any information from the administrators concerning a preferred bidder.
"On 27 January the EFL and Derby County's administrators, Quantuma, announced a four-week extension to the deadline for the provision of evidence of sufficient funding to complete the current season," the league said in a statement.
"The administrators have not yet provided that evidence, and we await an urgent further update from them on both that and the announcement of a preferred bidder."
Fears that Derby, a founder member of the Football League, could be liquidated receded when it was announced earlier this month that Middlesbrough had reached an accord with former Rams owner Mel Morris over their legal claim against the club.
The Boro claim, plus a further one from Wycombe, had been cited as obstacles to a takeover. There has been no update from Wycombe or the administrators concerning that claim.
The US-based Binnie family made a formal bid for the club in January, while a consortium put together by General Sports Worldwide is also interested in buying the Rams.
Derby were placed in administration last September by Morris. The club have been deducted 21 points for entering administration and for admitted breaches of EFL financial regulations.
The team are fighting for survival under manager Wayne Rooney and are currently eight points from safety.