No push notification OnePlus 8T Android 13

Hi. I downloaded the app today and everything works except for the push messages. I had to set the whole thing via the browser because it didn’t save anything on the smartphone. Why is that because it’s the only app that doesn’t send me a message as soon as there are new messages?

I have the notification settings set to “unread stories and Android”.

Info:
Android 13
OnePlus 8T

The RSS feeds were put through the “siftrss” filter and then included in the app (if that might have something to do with it)

Edit:
I’ve now also added an RSS without the filter to see if that might be the issue.

Thanks for the answers