Hallo Mihai,
First Idea:
After an unplanned power outage, the system time and/or the license validation may have failed.
Please verify the date and time settings and restart the Milestone Management Server service.
In most cases, the license will be valid again after this.
If the issue persists, the license needs to be re-activated.
Second Idea , check the Network connection and DNS function.
if the Error not disappear please open a support ticket at support@mobotix.com and provide the follow infos as described in the follow Community report: