c# - How to access delegated calendars from other organization -

i developing application targeting office 365 needs access shared (delegated) calendars available signed in user. use ews api according documentation - explicitly specifying calendar owner's smtp email address this:

<m:parentfolderids>     <t:distinguishedfolderid id="calendar">       <t:mailbox>         <t:emailaddress>primary@contoso.com</t:emailaddress>       </t:mailbox>     </t:distinguishedfolderid>   </m:parentfolderids> 

this works calendars shared users same organization signed in user, doesn't work calendars other organizations. same message in response:

<m:messagetext>the smtp address has no mailbox associated it.</m:messagetext> <m:responsecode>errornonexistentmailbox</m:responsecode> 

at same time can sees such calendars (and appointments) in owa ui - in "other calendars" section.

is limitation of ews api/office 365, or missing something?

this limitation of ews. when access shared calendar ews, goes server , opens owner's mailbox. when "sharer" outside organization, can't that. error you're seeing because ews tries resolve owner's email address mailbox inside organization , fails.

sharing outside organization done via publish method outlook or owa client never has access owner's mailbox directly. ews doesn't know how access information.

from sharing message, appears access ics feed, you'd need somehow url feed. in initial message sent user when owner shares calendar.