SharePoint Calendar Integration with Outlook

[Eric Adler]

Has there been a change in regards to using Outlook to view/interact with SharePoint (O365) calendars?

All of our users are seeing 401's regardless of site permissions (Member to Site Collection Admin)

Set up is EXO and SPO. EXO is in a hybrid architecture. We are using Outlook 2016 CTR.

I get this Outlook not Exchange, just wanted to put out all the variables I can think of. :)

Thanks,

eRic

[#2]

SPO calendars synchronized to Outlook do nothing to see what EXO calendars so that's not the cause of your issue. AFAIK, there have not been changes in regards of synchronizing SPO calendars in Outlook

[#3]

Ok, odd. We are seeing 401's across the board. Hmm...

Any troubleshooting suggestions?

[#4]

Hi Eric, 

Were you able to resolve?

What version of Outlook are you running?  Is it Office 2013 by chance?

We're seeing the same issue with Outlook 2013 connecting to SPOnline calendars.  We also had issues with Word/Excel/OneNote accessing documents in SPOnline.  Users would receive a login prompt that they could not get past.

However this was resolved by enabling modern authentication.

[#5]

Oops sorry I just re-read your post and see you mentioned it was Outlook 2016.

[#6]

For anybody else that happens to run into the 2013 -> SharePoint Online issue, these files must be updated to this minimum version for ADAL to work:

File name	Install path on your computer	Where to get the update	Version
MSO.DLL	C:\Program Files\Common Files\Microsoft Shared\OFFICE15\MSO.DLL	KB3085480	15.0.4753.1001
CSI.DLL	C:\Program Files\Common Files\Microsoft Shared\OFFICE15\Csi.dll	KB3085504	15.0.4753.1000
Groove.exe	C:\Program Files\Microsoft Office\Office15\GROOVE.EXE	KB3085509	15.0.4763.1000
Outlook.exe	C:\Program Files\Microsoft Office\Office15\OUTLOOK.EXE	KB3085495	15.0.4753.1002
ADAL.DLL	C:\Program Files\Common Files\Microsoft Shared\OFFICE15\ADAL.DLL	KB3055000	1.0.2016.624
Iexplore.exe	C:\Program Files\Internet Explorer	MS14-052	Not applicable

It's mentioned as part of the MFA requirements, but I haven't seen it mentioned anywhere as part of the ADAL requirements or as a solution to the Office 2013 credential prompting issue that you'll find yourself running into if you don't have a completely up-to-date 2013 MSI install.

I'd also recommend clearing the HKCU\Software\Microsoft\Office\15.0\Common\Identity key and Identities subkey, and adding back EnableADAL and Version as DWORDs with a value of 1 to enable ADAL.

If there's not a GUID_ADAL key under HKCU\Software\Microsoft\Office\15.0\Common\Identity\Identities after you make an Office->SharePoint connection, then it's not working and ADAL isn't being used.

Hopefully this is helpful to someone else so they don't have to track down the problem.