This app has not been functional for many premium users for at least two months. Despite the fact that Crunchyroll is aware of the issue there is yet to be an official fix, which is extremely frustrating considering it exclusively effects their paying customers.
If you are considering a Crunchyroll premium membership for manga, I would advise against it at this time; despite their excellent selection there is simply no way to read manga on ios for many subscribers. This all seems to show a staggering lack of care for their paying user base, I had really expected more from them.
Q. Quire about Manga by Crunchyroll, v2.1.2