A new block sealed in 6 hour on average in my POA private chain using AWS EC2. Why?How do I increase the frequency?

Question

As title：

My AWS EC2 spec. is ： 1 vCPUs, 2.5 GHz, -, 1 GB memory, 30GB SSD ,a free testing VM.

My init command is:

geth --datadir "." --networkid 15 init "./CustomGenesis.json"

and then,using following command：

geth --datadir "." --nousb --http --http.port 8545 --port "30303" --http.api "db,eth,net,web3,personal" --syncmode "full" --unlock 0b9331e020335d4cab5e00cea9de3xxxxxxxxxx --password "./password.txt" --mine --allow-insecure-unlock --networkid 15 console

When I enter the geth console，I use miner.start(1) to mine.

The console shows these message repeatly:

INFO [10-29|19:11:05.775] Writing clean trie cache to disk         path=/home/ubuntu/chain/geth/triecache threads=1

INFO [10-29|19:11:10.450] Regenerated local transaction journal    transactions=5  accounts=1

INFO [10-29|19:11:10.765] Persisted the clean trie cache           path=/home/ubuntu/chain/geth/triecache elapsed=1.970s

After about 6 hoers,a new block seased.

My genesis.json is belowed:

{
"config": {
"chainId": 15,
"homesteadBlock": 1,
"eip150Block": 0,
"eip150Hash": "0x0000000000000000000000000000000000000000000000000000000000000000",
"eip155Block": 0,
"eip158Block": 0,
      "byzantiumBlock": 4,
      "constantinopleBlock": 5,
      "petersburgBlock": 0,
      "istanbulBlock": 0,
      "clique": {
        "period": 15,
        "epoch": 30000
      }
},
    "nonce": "0x0",
    "timestamp": "0x5f9bcb9c",
    "extraData": "0x00000000000000000000000000000000000000000000000000000000000000000ad712c9171102d7eaf86d29589944411e3a70450b9331e020335d4cab5e00cea9de36b9c514e3a40000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"gasLimit": "0x8000000",
"difficulty": "0x1",
"alloc": {
      "0b9331e020335d4cab5e00cea9de36xxxxxxxxxx": {
        "balance": "0x200000000000000000000000000000000000000000000000000000000000000"
      }
    },
"mixHash": "0x0000000000000000000000000000000000000000000000000000000000000000",    
"number": "0x0",
"gasUsed": "0x0",
"parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000"
}

Answer 1

I solve this problem.

The key methods are fixed by：

First,the genesis.json is not correct suitable for my POA. The best method to generate genesis.json is using puppeth tool.

Second,every mining machine use its own miner account. Don't use the same miner account among mining machines.