Problem Communicating with dish 775 and Searching for satellite signal 771

Yesterday morning all of my receivers stopped working and got a message 775 Problems communicating with dish. I went to check the satellite signals and it showed 94 96 95 and the rest all zeros. The whole home DVR still worked with recording that were previously recorded. Later that day the receivers displayed searching for satellite signal 771 and started to display TV broadcast intermittently. Checked power adapter the light was solid green. Tried to unplug and plug back in did not resolve problem. Then today my TV's started working again I have an appointment for a tech to come out and wanted to know if it was still needed and what would cause my boxes to go crazy with those error messages and to stop working.