The 29-year-old, who was a target for The Lions during the summer, was the subject of a new offer as manager Dave Tuttle looked to reinforce his squad ahead of the season run-in. But the deal fell apart after the two clubs failed to reach an agreement.
"Millwall were interested in taking Darren, and came in with an offer on Monday night," said Scally.
"But there were conditions attached that made it impossible to do the deal - and issues arose that wouldn't allow it to happen."