This one is a quite rare actually (thanks to Ali for telling us about it )
This happens when a manga has two different names like “Ai Kora” and “Love & Collage”. If you add “Ai Kora” to the download queue first, then later you happen to add “Love & Collage” to Download, “Love & Collage” will not be downloaded and get stuck at the downloading screen and vice versa (you add “Love & Collage” first, then “Ai Kora” later, then “Ai Kora” will get stuck instead”
You can work around this:
1. in Download, tap Delete (upper right corner)
2. choose the stuck manga, tap Delete selected (lower right corner)
3. then add the series other names to download (if “Ai Kora” gets stuck, add “Love & Collage” instead, you can use onemanga.com to search for manga with different names)
We are sorry for any inconvenience caused, we will get this bug fixed in the next update of Manga Rock. Thank you all for your support and feedback!