Issue streaming 4K videos

Hi,
I hope someone can help me please. i am using the MyCloud Ex2 as NAS. it is conencted with the router via LAN and I am using the MyCloud App to stream content to either my mobile phone or tablet. For pictres it is just fine. However, when sreaming 4K Videos they “stop and go”. Can anybody help here please? Thank you.

Try running speedtest.net and find out how fast your connection is (rate limiting step is usually your internal wireless). 4k takes a lot of bandwidth.