Getting the error “Sampler error: unexpected frame type.” when reading a frame using Single Read Sampler with JMeter and JMeter Websocket Plugin

[Former user]

I am using Jmeter for the load testing of an application which includes web socket connection.

When trying to read the data in a frame using Single Read Sampler, got an error "Sampler error: unexpected frame type." and previous request reads are working fine

Please find attached the screenshot.

Can anybody help me in solving this issue?

[Peter Doornbosch]

The unexpected frame is a close frame, so that means your server is closing the connection. Unfortunately, it does not tell why ("reason: null"). It could be a timeout, or that the server detected an error in the communication that your test script is having with the server (so an application protocol error, not a websocket protocol error). My advice would be to check your server logs or try to run the server with debugging switched on.

Hth, Peter