Nginx Helper does not clear the cache

I’m using the latest version of the “Nginx Helper” plugin 1.9.11, together with easyengine and redis installed with the built-in eansyengine commands.
the cache works fine, but it is only cleaned with the “Redis Object Cache” plugin, the “Nginx Helper” plugin does not clear the cache the prefix settings are set in both plugins.
The Nginx and php logs do not report errors and the “Nginx Helper” plugin log reports that everything went well but the cache is not clean.
I am using Ubuntu 16.04 64x with easyengine, I have several sites created with the command “sudo ee site create example1.com –wp”, “sudo ee site create example2.com –wp”, …