Hey I had this too some days ago. I fixed it by just log out fully and then login freshly into dtube. Also I have problems with browsers except Firefox. So this is my dtube-browser. Also i had some troubles with large video files. Handbrake is good to reduce the filesize. Wish you luck !
Omg I really didn't think about logging out haha. And it worked! Thank you so much. Really appreciate your help. :)