If you are receiving an error message on Fox Sports on Roku that says "You have exceeded your account limits for this service: Invalid", it could mean that you have reached the maximum number of devices allowed to stream content on your Fox Sports account.
Fox Sports limits the number of devices that can stream content simultaneously using one account to prevent account sharing. If you try to stream content on more devices than the allowed limit, you will receive this error message.
To resolve this issue, you will need to log out of Fox Sports on all devices and then log back in on the devices you want to use. Make sure you are only streaming content on the allowed number of devices.
If you continue to experience issues, you can contact Fox Sports customer support for further assistance.