SharePoint SE OIDC Microsoft Office Authentication

Faisal Shahin 6 Reputation points
2025-05-23T08:23:11.04+00:00

Hi all,

I have deployed a SharePoint and Project Server Subscription Edition environment and configured OIDC to a custom OIDC Server.

Everything works Properly in Project Server Side except opening the schedule in Microsoft Project Professional It throws an error that it can't connect to the server

error

though it still shows the login page from the OIDC server after the login I get the SharePoint Error page

when investigating the log Found multiple SPApplication Authentication ModuleV2: Endpoint is not allowed for application authentication errors the wiered thing is if you try to open a word or excel file in the backend you see that sharepoint generated error but the document still opened correctly

here is the log file from ULS

ULSError.txt

many thanks in advance

Microsoft 365 and Office | SharePoint Server | For business
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  1. Camila Th 1,945 Reputation points Microsoft External Staff Moderator
    2025-05-23T10:08:37.5133333+00:00

    Hi @Faisal Shahin

    Good day! Welcome to Q&A forum.

    Do you mean when you open the schedule in Microsoft Project Professional It throws an error that it can't connect to the server?

    Where do you meet this issue? Which operation caused this error? Could you please provide your page screenshot?

    If you open the schedule from project server when you met the issue, your issue is more related to Project server, please kindly understand that the SharePoint server management tag here we mainly focus on general issues about SharePoint. In order to better solve your problem, it's suggested that you could post your case in project server forum for Results in Microsoft 365 and Office - Microsoft Community for more professional advice.

    Hope these information helps.

    Please do let us know if you have any further queries.

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  2. Alexey Roshka 0 Reputation points
    2026-06-25T08:58:12.2+00:00

    Hi,

    We are experiencing the exact same issue. The Project Professional client is not working with OIDC authentication.

    Environment details:

    Microsoft® Project® Online Desktop Client MSO (Version 2605 Build 16.0.20026.20182) 64-bit

    SharePoint and Project Server Subscription Edition with June 9, 2026 (KB5002873) CU

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