When I signed up for Zoho mail I made the admin for the domain account password 100 charters using a password manager. Although I can log in fine any action that requires confirming with the current admin password (ie delete account, reset user password) fails with a "Invalid Input" error, which I presume is due to the long password. Using Fiddler (web debugging proxy) I discovered that the operation fails with a HTTP 500 Internal Server Error status code.

Thanks