Unlocking challenges (not achievements) require completion of operations under normal networking. Cloud archives and automatic archives are not the same thing. Automatic archives are local, and cloud archives are from Ubisoft servers.

For example, when you exit the game, you will save the cloud. If you fail, it means you do not link to Ubisoft's server, and the challenge you completed will not be completed at this time.

Challenges

The first two are escaping from Templars and entering the machine for the first time.

One is from the Assassin's tomb.

One is to enter the upgraded 2.0 machine.

One is "Start Play Assassin's Creed 2" should be given if you open the game.

One is "Buy All Club Rewards" me.

The challenges except for buying club rewards are all the plot.

As long as you collect all the results, there is no reason to not be completed.