I've launched several substrate nodes in several clouds, one of which is Digital Ocean. The telemetry at telemetry.polkadot.io works just fine, it shows all the nodes and block generated in the real-time.
The problem is that https://polkadot.js.org/apps/#/explorer doesn't connect to any of my blockchain nodes, with the error message "The operation is insecure."
This is how I launch my cloud node:
./target/release/node-template \
--chain=customSpecRaw.json \
--alice \
--validator \
--rpc-cors=all \
--rpc-methods=Unsafe \
--unsafe-rpc-external \
--unsafe-ws-external \
--no-mdns \
--telemetry-url 'wss://telemetry.polkadot.io/submit/ 0' \
--prometheus-external \
--name='Digital Ocean Cloud Node'
Allowing all inbound and outbound traffic on ports for tcp, http, https (ports: 22, 80, 443) on my cloud VM didn't solve the problem.
I'd be grateful if you tell me if I'm doing something wrong.