**UPDATE**
Our investigation determined that a certificate was recently deployed to replace an expiring certificate; however, we failed to initiate a process to whitelist the new certificate. We’ve whitelisted the certificate to restore service but users may still have a token within their client which is associated with the previous certificate. To resolve the issue, users can sign out and sign back in to one of their Office desktop applications. Alternatively, the token will expire after eight hours and a new one will be issued. If users wait for a new token, the latest that the token will expire, and that service will be restored, is 1:15 AM UTC on March 15, 2017.
We received multiple reports of an immerging issue:
“Sorry, there was a problem while trying to connect to your account with error code 0x15”
This appears to be affecting systems using Shared Computer Activation and Office 365 ProPlus with legacy authentication. Our Product Group team is currently conducting an investigation and identifying solutions for this issue. Office 2013 ProPlus is configured to use legacy authentication (IDCRL) by default and many of the customers reporting this issue are on this version. Please note the end of support for Office 365 ProPlus 2013 was on February 28, 2017. Therefore, we strongly recommend to upgrade to Office 365 ProPlus 2016.
Enabling ADAL on Office 365 ProPlus systems has worked as a possible workaround while the product team determines the cause of this. For 2016 versions of ProPlus builds, ADAL is enabled by default.
The following documentation provides information about how to enable ADAL:
– How to enable the registry key for ADAL
https://support.office.com/en-us/article/Enable-Modern-Authentication-for-Office-2013-on-Windows-devices-7dc1c01a-090f-4971-9677-f1b192d6c910?ui=en-US&rs=en-US&ad=US
For Office 2016: HKCU\SOFTWARE\Microsoft\Office\16.0\Common\Identity\EnableADAL
– Verify that the ADAL .dlls files are the minimum required builds for this to work properly:
https://support.office.com/en-us/article/Using-Office-365-modern-authentication-with-Office-clients-776c0036-66fd-41cb-8928-5495c0f9168a?ui=en-US&rs=en-US&ad=US&fromAR=1