Thank you for the quick response Peter.

Have, as you say, discarded all user variables in the Domoticz Spotify plug-in. I also thrown away the installation of the plug-in in the folder "/volume1/@appstore/domoticz/var /plugins/domoticz-spotify-master".
I have placed a downloaded (clean) version ...

Get this errpr

Error calling 'http://localhost:8081/json.htm?vvalue=&vname=Spotify-refresh_token&vtype=2&param=saveuservariable&type=command'


I have exactly the same error.
It looks like the string of the Code part is too long for the user variables. So it cannot be stored there

Anybody ...