First of all, rather than having the combined fragments of success (on two levels) and error (inside the loop only) you should use opt for the one outside the loop and alt with tho alternatives (one for success and one for error). Obviously, the success/error is a condition in this case.
If you keep it like that, within the loop you actually expect to first success and then error happen in every iteration of the loop.
Now the second issue is, I don't see the loop anywhere in the description. There is just conditional flow where you may either have success or an error. There is nothing about repetition of the GET call. You also do not indicate properly the timing between the 200 response and the GET (there is a notation to show timing).
While technically this is not wrong, you may consider using the combined fragment of break for handling errors. rather than alt. But that's just an idea.
I may have missed something.
Disclaimer. I'm not pointing you to specific documentation for a reason. I'm just bringing to your attention what errors you have and what should you look for. Searching for the proper notification facilitates learning and this clearly is some sort of a homework. So a rod instead of a fish.
