Indeed the phone itself should respond.
I could workaround this by setting static arp entry on the server machine?
Yeah, that might possibly help a lot with android phone issues. It'd be nice if you could make the router respond from its cache as well... but I don't know of any software that does that.
Possible thought: put all your android devices on a separate SSID with a separate subnet, and make everyone who wants to talk to an android device route through the router.
But wait...
When i use my phone and start a dlna search. It is no longer in powersave.
And it should respond to the arp request?
Maybe, though perhaps the DLNA server has given up arping at that point? Can you test with a laptop or something?
I really do suspect this is an Android thing, for example: https://stackoverflow.com/questions/18939300/android-device-is-ignoring-arp-queries
you could possibly adjust wifi settings to keep the wifi on all the time, but I find it all very flaky.
No i only have this device 
//edit
This is so odd.
So my device was on sleep mode the entire night.
I turned it on, did a dlna discovery and it worked?!
Then i browsed the web for like 5min. Tested again and it stopped working 
Checked the arp cache on the server machine and indeed no entry for the phone there.
So it is quite random when it stops working.
Well the good news is it sounds like your multicast setup is working. The bad news is you have similar network reliability issues with Android that I have experienced.
Try setting a static arp entry for your phone, and see if it works around the issue. You'll also need to set up a static DHCP reservation for the phone, or use a static IP on the phone.
static dhcp entry is already set.
with the static arp entry is seems to work quite well.
but is it really the phone ignoring the arp broadcast/request or does the arp broadcast/request not reach the phone?
Is there wireshark for android available?
I think there's evidence that some versions of android ignore broadcast packets at least some of the time. Perhaps later versions of android fixed this, post 6.0.1 supposedly, but I have 6.0. It's also a big problem for ipv6 connectivity because the device ignores router advertisements.
This phone is quite old.
Samsung S5 but lineageos (7.1.2) supports it.
So it seems like evennewer android versions are still buggy x)
//edit
I tried to do some more debugging on my phone.
It seems like lineageos is using toybox and not busybox.
the arp command i broken. Something like arp no address associated with hostname.
i installed busybox. arp works now.
After rebooting the phone, the phone has an arp entry for my dlna server.
When i ping my network camera on the same wifi. It doesnt work.
arp shows the hostname and ip but not the mac. it states
Sometimes i also cant ping the phone itself.
Weird...
Okay. Seems like the problem is 802.11w.
With it enabled. arp broadcast are not delivered.
Now im not sure if its the router bugging or the phone.