I just switched to a new modem last night (from the Comcast modem to my own). Everything works on my roku except the xfinity streaming app. I know lots of people have had this issue. Serial numbers match what's listed on my account. Customer service has been no help.
ComcastElla, if you're still online, it seems like you've had lots of success.
Hello, snwbrd! Thank you for posting! I can check your account and make sure that we have correct modem info. I got your private message and will reply back in a minute.