The first tank taken out of the factory was on September 8 1915 and had the tracks fall off by September 10, it was quickly rebuilt and presented in front of officials but then broke down again, after they continued development on tanks they faced other problems like breaking or getting stuck in muddy terrain.
common word used by soldiers "ditching"
The inside of the tank had problems too like it always being extremely hot, and the fumes coming off the tank would most of the time choke the driver, and last but not least was the ammo for tanks it was always ammunition hungry.
hope this helps.