The client log "Error sending message: 404", after the remote server reboot

[lambochen]

Bug description
The client reports "Error sending message: 404", after the server reboot.
logs: ERROR io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.lambda$sendMessage$0 - Error sending message: 404

Environment

• Spring AI + MCP(0.8.1)
• spring-webmvc MCP remote server, sse

Steps to reproduce
step 1: launch MCP remote server, and client connect successful by 'http://localhost:port'.
step 2: remote server reboot.
step 3: print error log from client.