I have two Roku devices experiencing the same issue. Initial streaming connection intermittently fails to get establish. This began Thursday 9/5/19. I've removed the spectrum application and added it to no avail. This is occurring on all channels. Roku devices timeout and reboot. Subsequent attempts are sometimes successful. However when changing channels, I sometimes experience the same issue. Roku Stick 3800x, yf006m872484, 9.1.0 build 4919-55, wireless connection. Roku Ultra, 4660rw, yj00c4656892, 9.1.0 build 4919-46, ethernet connection. I've had no issues streaming with other apps or watching TV on my PC through my Spectrum account. My last Roku update was the night before this all began. Spectrum has escalated the issue. 
ISSUE RESOLVED!!! Spectrum contacted me today at 5 PM DST and stated that the problem has been resolved and I've been able to confirm on both of my TVs using Roku devices. Spectrum said this issue was relegated to the Gorham, Maine area only.

I am having the exact same issues on a Roku Ultra V.4 and Roku streaming stick.

Also began Thursday evening and seems to be even worse this AM. Seem to notice a slightly different spectrum menu, so assume it is an issue with there update. But very frustrating, especially on opening weekend of NFL season.

Please let me know if you find an solution, I have tried removing and reinstalling everything to no avail.

Thanks

It's not just you and you won't be able to fix it either by uninstalling or reinstalling the Spectrum App, or logging out and in of that App. Yesterday, I finally got through to Spectrum Tech Support and through their escalation process talked with a Tech Support supervisor. They had just starting receiving reports of this problem on Friday. They gave me a case number and are supposed to get back to us within 72 hours. One of the folks that I talked to on the way through the escalation process told me that the version of the Spectrum App that I am running is older than expected, but that is the one that you get from the Roku Streaming Channel Store.

This problem does seem to coincide with the Roku System 9.1.0 update which came out on 9/5. I have the same misbehavior on both my Roku units; only the Spectrum App seems affected.

Thanks for the notes here. 

Spectrum is aware of the issue and is investigating. Please continue to follow up with Spectrum support to share your reports and request additional assistance. You can reach them here: https://www.spectrum.net/contact-us/

Thanks,
Tanner

I am having a similar issue with a TCL Roku television. I go to open the Spectrum app and it will not work. This is not occurring on my other tv’s with attached Roku devices in their hdmi slots, just the dedicated TCL Roku television. I contacted Spectrum and they said it was related to a Roku firmware update. Is this the case??? If so, what/when will a solution be updated??? Thanks.