Questions regarding で, に

2018-02-06 22:15:48

ロビーが満員で入室できませんでした

悩み事で眠れない

Does this で mean "because"? If so, can it be replaced by だから、なので and/or だということで? (I think that で in the first sentence is supposed to be だ/です, but can it be translated as "because"?)

I think that に can also mean "because" at times, would it work this time?

ロビーが満員に入室できませんでした

悩み事に眠れない

Regarding the second sentence, is the で used the same (だ/です)?

As you can see, I'm a bit confused with all these way of saying the same thing.