There might be a connection problem between the PSU and hashboards what I would like to suggest is to replug all cable between PSU and hashboard.
If not, try to factory reset the miner by holding the reset/IP set button for 4-15 seconds then release.
Then set up the pool and test it again.
If it doesn't work your only option is to contact support but if you bought it 2nd hand I don't know if they can help you.
Try the troubleshooting guide from the link below
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https://www.zeusbtc.com/articles/asic-miner-troubleshooting/1753-how-does-innosilicon-quickly-determine-the-location-of-the-fault-through-the-fault-code