mail is not triggering when we recreate user on dropbox

Thanks for the additional details! Since you're getting the user_already_on_team error on the second addition attempt, it make sense that you're not getting the welcome email that second time.

That leaves the problem of why you are getting this error though. I still can't seem to reproduce this using these steps, so we'll need to look into it more specifically for you.

Please open an API ticket with the unredacted output so we can check on it. If you could also include the response headers, that would be helpful. (Just don't include the access token of course.) Thanks in advance!