Having same issues. Prime, Vudu, Disney + all give me error messages when I try to log on out of my Roku Ultra devices. Have contacted Roku support and none of the info they have given me works. Everything works fine on my laptops and Google Chrome. Looks like I'll be replacing all my Rokus with new devices this Christmas. Epic fail Roku!
Please provide us the following information for further investigation:
-Roku device model
(these can all be found in Settings > System > About)
-Does this issue occur on a specific channel? If so, what channel and what version/build is the channel (this can be found by selecting the channel on the Home screen and pressing the * button)
-Tracker ID when this issue occurs (when you see this issue occur, press the Home button 5 times, followed by the Back button 5 times)
-Steps to reproduce the issue you are seeing
Once we have the information needed, we'll be able to forward it to the appropriate Roku team to investigate further.
I tried to perform Factory reset on my Roku Ultra because the unit stopped working after 10.5 OS upgrade. The Roku banner appears then the unit stops sending HDMI signal to TV. Early Tech support has been sketchy at best I am hoping Danny-R at Roku can figure this out. Others have had some luck
Posted serial and device info. Roku rep Danny-R sent update overnight (to revert to 10.0). Upon applying the update (from 10.5 down to 10.0) my 4660X returned to normal. You might try a PM if you don't want sn numbers posted.