Thanks for the post.
If the issue remains unresolved, I'd recommend reaching out to Peacock directly to report the issue and request additional support. Many channels on the Roku platform are developed and maintained by the channel provider directly, and they'll be able to best assist. If other channels are working correctly, and you only experience this issue on the Peacock channel (app), that is likely an indication that the issue lies within that particular channel. In these cases, the channel provider will need to investigate the issue in order to help resolve it.
Thanks,
Danny
I believe that I've fixed it; I had to add some entries to my router whitelist:
services.brightline.tv # for Peacock
nbcume.hb.omtrdc.net # for Peacock
Now Peacock is working.
Thanks for your help!