に悩まされています

be troubled by

→ に
phrase Rare #36,863
be troubled by A polite form used to say that someone is suffering from or being troubled by an ongoing problem, illness, or nuisance. The thing causing the trouble is marked with に.
JA: 最近、仕事のストレスに悩まされています。
EN: I've been troubled by work-related stress lately.

ドイツ首相は移民問題に悩まされています

The German chancellor is struggling with the issue of immigration.