Outlook Calendar Synchronization error: (503)


I have an Outlook account included in eM Client; every time the program checks for mail I get the following error:

Synchronizing folder ‘myhotmailaccount/calendar/’ failed due to the following error: The remote server returned an error: (503) Server Unavailable.

I know several other people with the same problem; they each have the latest version (except they are using Windows 7).

I am using version 6.0.22344.0 in Windows 8.1 64bit.

I’m hoping someone may have a solution to this?

Thanks in advance for any help.

Hello, this is unfortunately a known issue to us, it can occur when the Outlook.com servers are not able to process the volume of requests being sent to it, the issue should automatically be resolved by the application by retrying the access and re-uploading the item you’re trying to synchronise or that the application is trying to synchronise.

This issue occurs in your calendar, so the problem is with a calendar server, but unfortunately on this type of account it is not possible to synchronise the calendar using a different protocol, however you can setup your mail account as an IMAP/SMTP server which would allow you to synchronise your email items properly. It would however disable the ability to synchronise your calendar and contacts items with the server.

Thanks Paul,

I did wonder if it was something like that.
I have noticed that on some rare occasions it does work without the error, so that does explain it.

Perhaps some sort of notification that displays the last time it successfully synced could be useful?

i.e. mail last synced… calendar last synced - or perhaps that is mentioned in the Log?

Thanks again for your time.

Thank you for the suggestion, I agree, we’re currently working on an upcoming release which will feature a re-designed UI, one of the first mockups have included this option, so I believe it should be included in the final as well.


Great news, thanks again Paul.


Is there a way to tell it to NEVER tell you about error 503 calendar sync again?

So, can I ignore the notice of error 503? 
Will it cause issues down the road? 
Will it be gone with the upgrade to 7 when that comes? 
Will I be able to upgrade since I have a free account?

I agree. These occur very often for me too and it would be great to have an option to always ignore these error; especially since the client will retry to sync.