Symptoms

Office365 tasks fail with the following errors:

 error id "validation-error", setting id "Configuration":Method edit_customer calling failed. Reason:Keyset does not exist Method: ValidateOrder

or:

error id "validation-error", setting id "Configuration":Method edit_customer calling failed.
Reason:Found multiple X.509 certificates using the following search criteria: StoreName

Cause

Insufficient permissions on certificate.

Resolution

Log into Office365 Endpoint server and check the certificate private keys permissions:

  1. Check what certificate is used for the 'Mosi' site in IIS via Bindings > Edit
  2. Open the Microsoft Management Console (MMC) and add the Certificates snap-in:

    • In the top menu, go to File > Add/Remove Snap-in.
    • Select the Certificates snap-in and click Add.
    • Select the Computer account option and click Next.
    • Select the Local computer option and click Finish.
    • Click OK.
  3. Go to the Personal > Certificates folder, right-click the required SSL certificate and choose the All Tasks > Manage Private Keys.
  4. Check if IIS AppPool\IIS_mosi_pool_name identity is added. If not, then add it in the following way: add > change locations to local computer > add IIS AppPool\IIS_mosi_pool_name > read only

Internal content