What could cause alien civilizations to be stranded on earth?

I'm not talking about a single alien civilization that is stranded on earth, I'm talking about multiple civilizations that will cause major overpopulation on earth. So this means that the civilizations have to be able to live on earth-like planets.

My first thought is that their fuel source for some reason decays or doesn't work in the conditions of our solar system or the milky way, how realistic could this be?

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What could cause alien civilizations to be stranded on earth?

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