The connection with a esdb://my.host:2113?tls=true fails with the message: “Error starting gRPC call. HttpRequestException: The SSL connection could not be established, see inner exception” and the deepest inner exception is a Win32Exception (0x80090367): No common application protocol exists between the client and the server. Application protocol negotiation failed."
I’m not sure if this is a problem with the client or the server, and if this is the right place for this question, or if this is a gRPC bug or even lower level bug…
I did a network capture and found the server is rejecting the Client Hello with a “No application Protocol (120)”. It does so with a TLS 1.2 record. I compared it to a Client Hello for a curl POST request on https://my.host:2113/admin/scavenge
There’s 2 things I noticed:
- There is no supported_version extension
- The only ALPN Protocol is h2, whereas in the curl request, there is also a http/1.1 protocol
- I’m hitting a single node server, version 18.104.22.168 on Windows
- The client is .NET 6 preview app, also running on Windows, using Grpc.Net.Client 2.38.0 / 2.39.0-pre1 (tried with both)