Serviio

I use Serviio on my QNAP TS-453, installed from QNAP repository via App Center. It looks that Serviio only support about of 20k audio/video/photo files (in summary). The problem is that my collection of photos is approx 250k. How can I increase number of files supported by Serviio?

Servio ver 1.8 PRO
QNAP firmware 4.3.3.01 54 Build20170413