The Kunduz siege, the first time the Taliban took control of a major city since being toppled from power in 2001 was a stinging blow to Western-trained Afghan forces, who have largely been fighting on their own since NATO's combat mission ended in December.
It was also an embarrassment for President Ashraf Ghani, elected on a promise to bring peace to the country after decades of war.
"The first biggest failure is leadership," said Amrullah Saleh, one of two heads of the Afghan fact-finding commission appointed by Ghani.
He said the Taliban had managed to seize 37 armoured vehicles and about 1,000 different types of weapons from the security forces once they had entered Kunduz.
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The national security council, which brings together advisors and ministers and is headed by Ghani, was also at fault, Saleh said, describing its heavy bureaucracy as "confusing".
Those Taliban involved in the siege took "instructions" from "someone in Peshawar, Pakistan"who had been planning the attack for at least a year, Saleh added.
The Taliban announced its withdrawal from Kunduz two weeks after the city's fall, though the government claimed to have recaptured it after three days.
NATO forces who helped to take back the city came under fire after a US air strike on October 3 pummelled a hospital in Kunduz run by Doctors Without Borders (MSF), killing 30 people, many of them MSF staff.
The medical charity shut down the trauma centre, branding the incident a "war crime" and demanded an international investigation into the incident that sparked an avalanche of global condemnation.