Unable to establish connection with ...

Copper Contributor

For the past 4 months, PMs in my organization have not been able to directly connect to our Project Server 2019 environment from MS Project Pro 2016.  They are receiving an unable to establish connection error.


These users all have the correct URL and rights to access the server from MS Project.  This all started after a Microsoft Semi-Annual Enterprise update was pushed through over a weekend.  We isolated this update as the issue because we rolled it back for certain users and they are able to connect to the server and access schedules without issue.  The second we push the update back to those users, the issue reoccurs.


This has virtually made the Project Server unusable.  We have found one workaround where the users open a link to a schedule file stored in a document library.  This forces authentication to the server and then the users are able to connect to the server and edit their schedules.  However, this only works for less than a day at a time and users are getting disconnected from the server in the middle of their session and unable to save/publish changes back to the server.  


If anyone has any idea what may be causing this or a possible resolution, please help!

1 Reply

Hello @mader1535 ,

I've not seen this before but I've not used Project Server on prem for many years. All I can suggest it try later updates for Project Professional to see if Microsoft have resolved the issue in a later patch, if you try the latest and it still doesn't work but does work on the earlier versions of Project Pro, I'd probably either stick with the earlier version of Project Pro or open a support ticket with Microsoft so they can investigate and get fix out (if they don't have one already).