Accounting and consulting firm BDO Seidman LLP missed the deadline for bringing a legal malpractice lawsuit against Morgan, Lewis & Bockius, the District of Columbia Court of Appeals ruled Thursday.

Morgan Lewis represented BDO’s Tax Solutions Group, a limited-liability corporation that was owned by BDO but run exclusively by three senior partners at BDO, according to court filings. The tax group later ran into trouble with the Internal Revenue Service, and BDO was hit with a class action filed by former clients that the company settled for $21 million.