I got a new roof on my house. The roofers removed my dish then put it back on. Now I am getting the message 771 signal loss. Could this be that I need to realign my dish or is it something else.

Odds are it needs realigned. I'd try that first at least as it's something that's easily checked .

Roofers may have disconnected a cable or something, I'd check that first.

Hmm or possibly damaged it.

First thing I would try is unplug your TV, let it sit for 10 minutes and plug it in again. An electronics guy told me this trick...the TV will reset and search for signal.

It may just be a blessing

X2
The alignment has to be just about perfect. You can even get the dish lagged back down in the previous holes and still be a bit off to get reception.

This. Haha

If its just an alignment issue I may try to do it myself I successfully done it once before. They screwed it back in the same holes but something is wrong. Yes it might be a blessing. I have thought about canceling several times. Any time you call customer service it takes ten minutes to get a human and when you do they hardly speak English. Direct tv used to have great customer service then ATT bought them and it went to crap.

I don't know about precision alignment when i had tv my dish was on a high trellis when i replaced and added on my deck i left that post in when it got very dry over summer i lost reception post twisted i guess pushed it over with a long pole till tv came back on in fall had to take it down after a couple years of this i canceled get my entertainment on here now

There's cheaper options out there if you got high speed internet. YouTube, sling, pluto have good options depending on what channels if any you actually watch