Seeking flac does not seem to work

[lineinthesand]

I don't know whether the problem is on MinimServer's end or whether my Networkplayer simply does not support it but I cannot seem to seek in flacs (or any other format I've tried for that matter) using e.g. the BubbleUPnP or HiFiCast Android Apps on a Yamaha Network Player.

My setup is as follows:
MinimServer 2.0.18 update 191 on a Synology DS220j (DSM 6.2.3-25426 Update 3)
BubbleUPnP (or HiFiCast) app on Android
UPnP renderer is a Yamaha NP-S303

I read on another thread that there is something like a MinimServer log window but I could not find out where that is. Is there anything I can do/provide to help debug this problem?