There is no active license for DIAFAN.CMS
The license for your DIAFAN.CMS isn't valid or ended therefore further operation with system is impossible.
To have an opportunity to manage the website, add your domain to the license in a private account for user.diafancms.com.
Why so occurred?
Most likely in a private account you forgot to register this domain in the bought license, and the trial twenty-day period was ended.
If you get this page when you trying to receive updates, it means that on the website the autoupdating code (generated from a data set about the website, the domain, a hosting, the CMS version) for example, because of change of ip of a hosting changed. Then you need to make request in support desk about change of a code of updates.
Check up DIAFAN.CMS license and their owner