shared notebook does not open on IPhone

[Kaethi 0]

Dear fellow users. I have been shared a notebook through my account mail. As soon as I open the link contained in the mail to access the shared notebook, I am redirected to Appstore in the Apple app, even though the app has already been downloaded. The notebook doesn't show itself in the corresponding section. 
When I try to open it in the browser on the other hand, it just doesn't show up at all. 
We tried several times and it still didn't work, unfortunately. 
Does anyone know what to do? 
thanks in advance. 

[PinkElephant 8,117]

It you can repeat the sharing, I would unshared the notebook first. Then both sides log out of their accounts, back in and repeat the sharing.

If this is not feasible, you can try to log out and back in again yourself. Sometimes this refreshes the app data from the server, and the share will show.