Tvheadend

I have two machines running tvh. One main server and a second sub-server. The main server takes some channels from the sub-server via http. Both servers are catching services from the same provider (OTA EPG). The problem is that channels from the sub-server (in the main server) have very limited EPG or sometimes no EPG. The sub-server has full EPG. I guess no EPG is transferred via HTTP ? so the main server must find EPG for the "http" channels which is does but not completely. How to fix it ?