Hello,
It is difficult to estimate the cause for what you have described, as no recurring issue is known.
Knowing your device, firmware and configuration details would be really helpful, thus I would like you to attach a troubleshoot file from the device generated after it stops transmitting the data. Please, make sure to replicate the issue, do not reboot, access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there. Edit your question for an option to attach the file.
Best regards,