Remote Connectivity Analyzer Exchange Web Services URL

Hi,

I may be being particularly stupid here, but...

I'm trying to test a connection using the Remote Connectivity Analyzer. As far as I can find out, the Exchange Web Services URL should be in the following format:

https://<server name>.outlook.com/ews/exchange.amsx

where the server name is the bit out of the 365 URL (something like: pod12345).

However, when I enter this into the field, I get an error saying:

"Error: This fi​e​l​d ​i​s ​i​n ​a​n ​i​n​v​a​l​i​d ​format or has invalid ch​a​racters."

Can anyone please put me right?!

Thanks in advance.