Of course it fails. By default partitions are mounted by UUID, which is unique for every harddisk. So now your fstab on the cloned disk contains the UUID from the original disk, which doesn’t match the cloned disk’s UUID.
You could boot the system from a Live USB, mount the root folder and change the mounting by UUID to the old way, i.e. /dev/sda1 etc. Once you’ve booted from a Live USB that shouldn’t be too hard to find out. AFAIK recent Ubuntu’s also use UUID in the fstab, but not 100% sure.
UUID is a sudo random number that is created when you create a partition and attached to the partition. So it depends on when you create the partition what number gets assigned. Cloning may or may not copy the number depending on the way you do it and tools used