MinimServer slow to detect

[dsb17]

I am running MinimServer on a QNAP TS-431 (I am also running the Twonly server on the same QNAP as a control). The QNAP is has a Ethernet connection to an Asus router configured as a bridge. The bridge connects wirelessly to the main router (also Asus). The control point is Foobar on a wireless laptop.

My problem: MinimServer is slow to detect in Foobar. It takes ~15 min (several tries in the last few days) before MinimServer is visible in Foobar. All the while Minimwatch reports that MinimServer is running. In contrast, a Foobar Media Server running on a separate PC is immediately visible, and the Twonky Server, running on the same QNAP as MinimServer, is normally visible within one minute.

I understand that UPnP over wireless is sketchy (in fact it took me a few days playing with network settings to get to the point of detecting MinimServer reliably after the 15 minute wait). Is there anything that I can do to shorten the time before MinimServer appears in Foobar?

Thank you,
Dario