Apple+ TV not loading on Roku Express

I've had a subscription to Apple+ TV for several months and I've watched it many times on my Roku Express. It's been a few weeks since I've clicked on it though, but now today it keeps saying, "Apple TV could not be run because there is not enough space. Please remove one or more of your installed channels and try again. To remove a channel, focus the channel, press *, and then select 'Remove channel'. I was at one time up to over 700 channels, but began removing them when this same issue occurred with Youtube, and it started working again. This time I was down to just a little over 400 channels, and so I began removing more. I am now currently down to only 348 channels. I have done a system restart and a system update many times, and I removed the app, did a system restart, and then added the channel back, but it still doesn't work. I need help with this issue.