You can view these steps and others at my BTCPay guide now: https://sethforprivacy.com/guides/accepting-monero-via-btcpay-server/#troubleshooting
A recent change to monerod
makes it write SSL certs to disk in its data directory, something that can fail if the permissions on the data directory are incorrect. You can follow the steps here to correct those issues and get monerod
back up and running.