Thanks for reaching out here in the Community!
Can you please provide us with more information regarding the issue you are experiencing? Does the issue only occur on a specific channel or all channels on your Roku device? What troubleshooting steps have you taken so far to try to resolve the issue? Are your phone and Roku device on or using the same network? How long has the issue been occurring?
We recommend doing basic troubleshooting steps on your device and checking if these steps would resolve: How to screen mirror your Android or Windows phone to your Roku streaming device
Hope you'll find this information useful. Let us know in case you've still got any questions.