The response code is ok but I’m getting html returned in the response which contains the text:
We're sorry! An error has occurred while processing your request. A report has been generated for our technical staff to investigate the problem. Please try to repeat your request later. Thank you for understanding.
If I wait a few minutes and try again it works. In the System Monitor → System Events screen I can see that there are `Sign-In limit exceeded` events, however I can successfully create new login sessions so I don’t think that is the problem.