Exchange Online EWS Access

Hi,

I have been having issues in getting EWS working with Exchange online each time i go to https://outlook.office365.com/ews/exchange.asmx i get a blank page and when I run developer tools in IE i see a 503 error. Our ADFS is not externally accessible and we are currently using password hash sync in staged mode

If I try with a pure cloud account i get the xml service page in IE but not if i use my Azure synced account. Anyone come across this issue?, microsoft support have been investigating for the last few months with no joy.

Thanks,

Vin