Upgrade to enterprise version fails

when I try to upgrade to the enterprise version, I get the error "file_get_contents( …url… ):failed to open stream: HTTP request failed! HTTP/1.1 401 Unauthorized
API key+secret are ok.
Update URL: https://update.pydio.com/auth/
Release-channel “Install enterprise version”.
Curret Pydio version 8.0.2 (Ubuntu 16.04 LTS)
What can I try to resolve this problem?
Many thanks,

to make sure the first step are right did you fill it as seen in this screenshot,
if it’s still doing the error you could empty the cache located in /pydio/data/cache and remove the plugins_ files, you could also restart your webserver and php.