Serviio v2.2 on QNAP TS-251A QTS 5.0

Dear Sirs,
I've just updated to QTS 5.0 and to Serviio v2.2 on my TS-251A and it seems my devices can't see Serviio DLNA server anymore. The GUI is working, I can see my shared content there, but none of my TVs or other devices on my network can detect Serviio and Serviio can not see them neither; all of the devices are unknown or inactive under connected devices.
Your suggestions to resolve this issue would be greatly appreciated.
Thank You very much in advance!
I've just updated to QTS 5.0 and to Serviio v2.2 on my TS-251A and it seems my devices can't see Serviio DLNA server anymore. The GUI is working, I can see my shared content there, but none of my TVs or other devices on my network can detect Serviio and Serviio can not see them neither; all of the devices are unknown or inactive under connected devices.
Your suggestions to resolve this issue would be greatly appreciated.
Thank You very much in advance!