I have a Martin firecat tr1 (single cam) that I bought new in '10 or '11, iirc.

Before I put it in storage in the hard case, it shot great and was zeroed.

I just got it out today and at 15 yards or so I had to use my bottom pin, which was set for 60 or 70 yards I believe to hit near the correct elevation.

I was also hitting to the left a few inches, which could be me but I stacked arrows on top of each other so if it's me I'm consistent. Lol. I noticed that I could see the arrow flying a bit sideways which makes me think that my rest could have been knocked out of alignment. It doesn't look obviously out of whack though.

I double checked to make sure I didn't dial the draw weight down before I put it away.

Was it climate controlled storage?

16 months of not shooting, you are probably shooting differently (anchor position different, facial pressure against the fletching, etc.).

It also could have gotten messed up in storage if not climate controlled.

Or both.

Strings probably stretched, cams out of time .

Edit. Just saw it’s a single cam. Disregard.

The storage units were kept from freezing and it was in western Washington, so the temps aren't extreme.

Maybe it's time to find an archery shop.

I kind of purposely didn't get into bows beyond shooting (for hunting) because I quickly saw the potential for it to blow up into another hobby that needs it's own shop/workspace. Lol

Single cams can still have string/cable stretch issues.

In the past I wanted a custom string so I could have a peep without the rubber tube.  Maybe this is a good excuse

If you hadn't bought strings yet, I'd suggest looking Catfish strings, Threadz, JBK strings or Archery Shack.