Cloning specimens doesnt solve the inherent problems that led ot these species becoming exctint, be it

lack of a stable population (major disparaty in gender+ long gestation cycles makes a species weak to long periods of scarcity),

a lack of suitable habitat(often because we over took them or in some way affected it negatively),

a change in the overall ecosystem that makes the current iteration of the animal unviable(like the dod for instance effectively only surviving in a place where they had no natural predators).

then you have the issue that a population of clones faces the real risk of a genetic bottleneck which can lead to a vulnerability to a pathogen and the follies that come with inbreeding.(ie the main cause cheetahs were andstill are in danger is because they have a significant genetic bottleneck making a lot of their population majorly inbred.)