I've checked key updates this morning and they were not working. Only the feedback-server was accessed.
I've checked it again ten minutes ago and now updates are working again.
Feedback-server AND key-server are now accessed and cURL timeout message is gone.
It seems Plesk is still testing.
Hello,
we are using the latest version of Plesk Onyx 17.5.x on serveral CentOS 6.9 and 7 servers. On two of the CentOS 6.9 servers the license key is no longer updated. On other servers with the same environment it still works.
If you try to update the key on the affected servers via Plesk...