First, do the Calibrate EL routine described in your manual (or download online). Hopefully, that will resolve the issue.
If not, then it's likely that you will have to replace the coax (one or more depending upon DISH or DTV) that runs from the LNB to the top of the base. This is the most common cause of that error. You can use a standard coax temporarily to see if it fixes the problem. If it does you can find similar pre-made cables online or you may be able to order new cables from Winegard.
What I post is my 2 cents and nothing more. Please don't read anything into my post that's not there. If you disagree, that's OK.
Can't we all just get along?