Please post the logs here so that we can check them for you, what is going on behind your unit or if you want to learn how to read and troubleshoot it on your own you can download the guide from this link below under manual then troubleshoot

- https://www.canaan.io/service/447

Also, check the pool where you mine, and maybe the issue is related to the pool server if you have unstable internet or high ping the miner will stop.