4-1 - Unsupported protocol

Possible Reason

This situation may occur in the scenario of custom Protocol. Dubbo’s SPI mechanism cannot find the Protocol specified in the URL.

Troubleshooting and resolution steps

1. Make sure that the Consumer has dependencies on the Protocol used by the server.
2. Make sure that the name of the SPI configuration file of the Protocol’s dependent package is correct.

see also

Dubbo SPI Overview

Protocol Extension Description