Boeing was hoping the troubled jet would be back in use by the end of June following encouraging signs from authorities, but this latest setback means a new certification is unlikely before the end of July.
"On the most recent issue, the FAA's process is designed to discover and highlight potential risks. The FAA recently found a potential risk that Boeing must mitigate," the FAA said in the statement emailed to news agency Reuters. "The FAA will lift the aircraft's prohibition order when we deem it is safe to do so."
Boeing was in complete agreement with the authorities on the matter and would continue to seek a solution.
"Boeing will not offer the 737 Max for certification by the FAA until we have satisfied all requirements for certification of the Max and its safe return to service," the company said.