Legendary catch

Sorry to hear that. There seems to be global issues with trying to interact with gyms right now, meaning you did nothing wrong, but had bad luck with timing :(

Research reward encounters allow you to flee and return, but raid boss encounters do not.

Ho-Oh...arguably the biggest target in the game, drifted right and you decided you couldn't hit it? His circle takes up half the screen.

When you have one of the easiest targets in the game, don't worry if it drifts right.

Just throw the ball and catch it.

In the future, just wait out any legendary movement rather than restarting. The chance of an error happening like you got is not insignificant.

In the case of HoOh, I can see waiting for it to descend when it flies up high (I do this), but its slight movement to the right shouldn't stop you from throwing at it by any means. A "straight curve" to the center of the screen will still hit inside an excellent-sized circle for it.

For the future, if you have a phone that can handle it, going in and out of AR+ mode also re-centers the Pokemon without having to flee the encounter. I do it all the time.