I am not sure whether its firmware issue or power supply issue as power supply is normal. Thanks.
I can't say if it's a firmware issue but it is more likely a PSU issue.
Can you still access the WebGUI or dashboard?
If you can still access through the miners IP would you mind to check the API logs or any logs that contains your miners activity logs. Maybe we can find the issue under that logs?
Post the logs here don't forget to put it inside the code tag a # button you can find it while editing your post.
Also, I would like you to try is to hard reset the miner by holding IP or reset button for 15 to 20 seconds then release.
Set up the miner again then test.