Reflection sphere resolution

I think my problem is related to this topic, so I ask a question here. I created my first interior in UE4.
I have a big problem with the mirror. Reflection is distorted and cloudy and have a low resolution. Reflection looks awful. I can’t keep it so. I don’t know another way how can I take high resolution reflection in my archviz scene. Maybe someone can give me advice about custom material for simulate realistic mirror?


Here’s a screenshot