Can't install fusion DSP on Volumio (Version 3.435)

System : Raspberry B3+ / Hifiberry DAC Plus
Volumio Version 3.435
freshly installed.
I try to install the Fusion DSP plugin. First it seems to work, but on the end I get an error.
“An error occured while installing the plugin: Error”
Trying to uninstall the plugin gives
“An error occured while uninstalling the plugin:Error”

Any idea what is going wrong ?
Thanks for help.

Is your date and time setting correct?

It is. Thank you for your interest. I just found the problem.
I dont like to have an widely open system in my network at home, so the first thing I do after install is to change the default user/password combination.
See also the thread: Volumio network security

The problem is, if you change the password for the user volumio, the plugin system doesn’t work anymore. Bad news.

I would recommend not to change the default PW, this might keep generating issues.
For some reason I don’t get all the fuzz around this, It’s a media streamer.
The only way that it would raise some issues, if when you decide to open your network for external access, which is also not needed as you can connect to it via myvolumio.