Unraid goes back to SLEEP after Wake on LAN

[xenos]

Hi, I have a problem. When I wake up my Unraid server via Wake on LAN, it goes back to SLEEP immediately (in a 1 minute). If I wake him up again (via WoL), everything is OK, but why it's not working on the first attempt? This problem occurs everytime. And I have noticed another thing, when the Unraid wakes up and I'm fast enough, I can see that the "uptime" of the server is continuing from previous session (like uptime is 19hours and 20 miutes), but after the second wake up (when everything is ok) the "uptime" is counting from zero again. I made it to take screenshots of the log before the "automatic" sleep.

Has anyone an idea what could be the problem?

I would be thankful for any advice.