Whoops! Got to Xero this morning and got this.

Looking at the address bar it appears that it’s sent me to the custom error page. And then the custom error page has thrown an unhandled exception which has been bubbled to the default error handler.

If ever there was a case for using ‘On Error Resume Next’ then Custom ASP.NET Error pages are it . Throwing an unhandled exceptin from your nice Custom Error page gives bad UX.

On the plus side, the Xero support people are just super and the actual application really rocks too.