Let's check to see what happened to your estimate, primeconstructio.
Could you remember what sign-in page was that for? You can try creating an estimate again to see if you get the same thing. If you do, please send us a screenshot so we can check it further. If not, you can find your previous estimate from the recent estimate list.
If your estimate is not on the recent list, this means it wasn't saved. Then, please let us know if you're still be routed to a Sign-in page, we can resolve it.
Have a good one!