Starting in February 2017, Microsoft will no longer support Project 2013 (through Office 365 or MSI) connecting to Project Online. Customers who need to connect to Project Online will need to move to Project 2016.
For more information, please check out Premier PFE, Brooks White’s blog here:
- After February 2017, no more support for Project 2013 with Project Online
https://blogs.technet.microsoft.com/brookswhite/2016/10/29/after-february-2017-no-more-support-for-project-2013-with-project-online/