Cambridge United are under severe financial problems following a dispute between the football authorities and the Inland Revenue.
The club has released a statement detailing the problem.
In essence, according to BBC Sport, talks broke down over the debt-hit club's plans to pay back creditors.
HM Customs are not happy with their share of repayments - and United will need to find emergency funding if a deal is not struck by Wednesday.
United are in administration and will not be allowed to join the Conference if they do not reach an agreement with their football creditors.