Does anyone know what the most likely culprits are for this error message?

./netclient join -k <key> -n <network> --apiserver api.<apiserver>:443 --grpcserver grpc.<grpcserver>:443
[netclient] joining <network> at grpc.<grpcserver>:443
[netclient] error installing: rpc error: code = Unavailable desc = connection closed before server preface received
Failed to authenticate: rpc error: code = Unauthenticated desc = Something went wrong with Auto Login: rpc error: code = Unavailable desc = connection closed before server preface received
[netclient] removed <network> network locally
[netclient] removed systemd remnants if any existed
[netclient] removed systemd remnants if any existed

I have seen it mentioned in the chat log but it didn't seem like any conclusive solution was mentioned