Although the previous 2 suggestions are great, I think I would save time and modify their suggestions.
(1) Remove power to all 3 receivers and the DPP-44.
(2) Remove the RG-6 for DPP-44 LNBF Input 1, replace the connector so that you have a long lead - about 3/8" past the thread will be fine.
(3) Remove the RG-6 for DPP-44 Receiver Output 1; replace the connector so that you have a long lead - about 3/8" past the thread will be fine.
(4) Apply power to the DPP-44, Receivers 1 and 2.
(5) Then do a Check Switch on Receiver 1. You will probably find satellite 119. If so, you know your DPP-44 connections were too short, and you will need to ensure all 3 inputs and 3 outputs are long enough. If not, then it is time to test the switch and power inserter; including by-passing them.
(6) Do a Check Switch on Receiver 2. If you find Sat 119, then the RG6 stringer for Receiver Output 2 is probably okay. If not, make it longer, as well as for Receiver 3.
NOTES:
- When you connect a DPP Twin LNBF to a DPP-44 Ports 1 & 2, Sat 119 will default to Port 1, and Sat 110 will default to Port 2.
- The RG-6 center conductor needs to be longer than most other applications for the DPP-44 to work. I think 1/4" will do it, but go ahead and put it 3/8" past the threads since the DPP-44 has plenty of room.
- If you are unable to immediately replace the connectors, then try splicing the LNBF cable by taking a small piece of coax with a long stringer and connect to the DPP-44 LNBF Input 1 and then to a barrel connector. Connect the other side of the barrel connector to the lead from the DPP Twin LNBF. This only to do a quick test of the connectors.