Can't help if you don't tell us which LNB you have and how the two are connected together.
Which decoder is not working? The primary or the secondary?
Check the network settings
Octo LNB; 2 by 2x4 MS; 2 by ES 5-2; Dedicated PSU for LNB, ES's, MS's; HD PVR 4P x 2; Explora 1; DSD 660; FSM
Make sure they are on different user bands. For instance my primary is on Decoder1 setting and my secondary on Decoder2 setting
and Cat6 | 200/100 Fibre (OpenServe/Afrihost Premium UnCapped) | HD 5S in holiday mode
I have 2 linked explora 2’s. Ons works perfectly, the other has no picture or sound. Channel info comes up, as well as catchup titles and playlist titles. Have rebooted 3x for 30 sec. No change. All cables secure. Please help.