What does mean "teething troubles"?

Question

What does mean "teething troubles"?
and where comes from this word?

Answer 1

Babies always have to suffer agony when they are cutting their first teeth. It is to be expected that when a business first starts it is going to encounter problems, but these problems are then sorted out and soon forgotten, just like the pain suffered by the baby at that early stage of his life.

Answer 2

It means the problems you have when you first try to do something, especially building a machine, or getting it to work.

Perhaps we say it becuase, just like a baby getting it's first teeth, it is not a serious problem, but makes you unhappy.