We have been running Project Server 2016 in an enterprise environment for many years with no issues. Fairly recently we switched all enterprise websites (including our PWA) to use SAML authentication. Since switching, from time to time certain users randomly receive this error message when trying to connect to a PWA site in Project Professional, and it stops working until we do our workaround: Project was unable to establish a connection with
The workaround we have been using is having them close all Office applications, having the user browse to an empty Excel or Word file located on the same site, opening it up in the client to refresh authentication there, and then Project Professional works after. The problem is that this is becoming quite an increasingly common inconvenience for more and more users and interrupts their flow of work.
It seems to be the case that for some reason, Project Professional in particular either refuses to refresh the SAML authentication or keeps trying to use stale authentication, however once we refresh authentication on a normal Office app (Word,Excel,etc.), it works just fine. We have tried various other fixes with no success, such as clearing a bunch of caches, changing settings in Project/Office, clearing out items in the Windows Credentials store, and even trying a brand new computer.
Has anyone else come across this and found a resolution?
