The problem is that your version of Sentinel and Feign are incorrect. In the new version of feign.BaseBuilder, the build method is final and cannot be overridden. There are problems with the SentinelFeign or CustomSentinelFeign overridden build methods configured in your project. You can change the override build() method to internalBuild(), or use the correct version of Sentinel.

Refer to issue 3514