"经常抱怨的问题" can be translated into English as "frequently complained-about issues" or "common complaints".
"Frequently complained-about issues" emphasizes the recurring nature of the complaints.
"Common complaints" is a more concise and commonly used expression, directly conveying the idea of issues that people often complain about.
Both are correct, and the choice between them may depend on the specific context and the desired level of formality.