Does the issue only occur on a specific channel or all channels installed on your Roku device? If it's just one channel, removing then re-installing it may help. To ensure the process is successful, follow the steps below making sure you restart your Roku device before adding the channel again.
Remove the channel: Highlight the channel tile on your home screen and press the Star button to open the options menu. Select Remove channel and confirm.
Note: If you are removing a subscription channel billed to your Roku account, you must cancel the subscription before you see the Remove channel option. For help identifying this type of subscription channel, read the detailed article about removing a channel.
Restart your Roku device: Restart the device from the settings menu. Go to Settings > System > System restart > Restart.
Re-install the channel: After your Roku device restarts, visit the Roku Channel Store and add the channel again.
Note: If you are adding a subscription channel billed to your Roku account, you will need to resubscribe.