Albert: In English, the verb agrees with the subject, not with the predicate nominative. The noun before the verb (or immediately after, if we’re using inversion) is the subject, while the noun after the verb is the predicate nominative. In your example, the subject of the main clause is “it”. Even though “it” is a dummy subject, it still governs the verb. The fact the word "AirPods" is plural is irrelevant in English.
Note: We don't say "failed working" (as a phrase), but rather "failed to work" (or simply "failed").