Why have the app if you can't use it?
I find it absolutely ridiculous that in order to watch videos I have to go into my ps4's web browser and pull up the funimation full website. Why is there even an app if you can't actually use it? Before the update the video player worked fine in the app, now it takes an hour to watch a 24 minute episode. Please fix the buffering issue in the apps.
One thing you might try is deleting and re-installing the app. That worked for me personally when it started giving me problems.
If you try that and your issues still persist, then please send in a ticket to www.funimation.com/contact-us, and let the tech team know about it. You can also try contacting them on Twitter @FunimationHelp, and you might get a faster response that way.