p2pool stops processing
I am running Seth's docker containers as per his [guide](https://sethforprivacy.com/guides/run-a-p2pool-node/#download-and-run-monerod-and-p2pool-via-docker) and have this morning updated the docker images to the latest available and restarted both the monero and the p2pool containers.

Unfortunately now it seems that p2pool starts and then just stops. Last message in the p2pool log says:

```
P2Pool get_miner_data RPC response is invalid, skipping it 
```

Xmrig can't connect to p2pool and asking for a `status` from p2pool shows:

```
2021-09-21 20:11:54.5566 SideChain status
Main chain height         = 0
Main chain hashrate       = 0 H/s
Side chain height         = 1
Side chain hashrate       = 10.000 KH/s
PPLNS window              = 0 blocks (+0 uncles, 0 orphans)
Your shares               = 0 blocks (+0 uncles, 0 orphans)
Block reward share        = 0.000% (0.000000000000 XMR)
2021-09-21 20:11:54.5566 Util no background jobs running
```

Monerod seems to be running ok, syncing with the monero network and monero cli wallets connected to the node work as expected.

What else can I do to trouble shoot?