Ring video doorbell live view doesn't work

Hi, I have 2 smartphones logged in with the same ring account. On one device, when receiving a doorbell call, the camera view stays blurry. When viewing the recording afterwards everything is ok. To make sure it is not a connection issue I also tested this on the same wifi network as the ring doorbell. When troubleshooting I noticed the same behaviour when trying the live view in the ring app. On the device that is working correct the live view starts with the same blurry view, after a second you get the loading icon on the blurry background and afterwards the clear live view. On the device that is not working the live view stays blurry and the loading icon won't show. Thé recording of that live view does work. I installed the 'rapid ring' app on this device and there the live view works perfect. Uninstalling the ring app, rebooting the device and reinstalling the app did not help. Changing wifi and cellular connection did not help. The doorbell device health info is ok. Any suggestions? Regards