Specifically, it's called pronoun ambiguity. This occurs when a pronoun could refer to more than one possible antecedent (the noun or noun phrase the pronoun is referring to).
For example:
* "The dog chased the cat, and it ran away." It's unclear whether "it" refers to the dog or the cat.
To avoid pronoun ambiguity, you can:
* Rewrite the sentence to be clearer: "The dog chased the cat, and the cat ran away."
* Use a noun instead of a pronoun: "The dog chased the cat, and the dog ran away."
* Add context to make the antecedent clear: "The dog chased the cat, and it, the cat, ran away."