[Solved]-Celery chain breaks if one of the tasks fail

That is the point.

Forming a chain means your subtasks have some kind of serial dependency: Each one only makes sense if the previous one has been performed.
Without this, you would simply use queueing or use a group rather than a chain.

So if one subtask fails (and still fails after attempting all its retries), the chain fails.

I readily admit that the documentation (as of Celery 3.1.18) is far from explicit in this respect, but the name suggests this semantics:
“A chain is only as strong as its weakest link.”