Offline Address Book is unavailable - 401 unauthorized

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Written by Support InfoBridge


An update to start this article: We now have the option of a new version which uses OAuth authorization. We advise you to upgrade to this version if you have a SuperOffice version higher than 8.5R14 to avoid the issue mentioned in this article. 
Extra Note: For older version we are also working on an updated version. Meaning we will have one Synchronizer version for all SuperOffice versions from 7.5 and newer.


Users of the Exchange Online Synchronizer and Office 365 will notice a warning when trying to load the external users in the Synchronizer admin. 


The way the synchronizer retrieves the addresses from OAB (Offline Address Book) is not available anymore in O365. This most likely has to do with the decommissioning of Basic Authentication in October 2020, more info

We were already working on a new version that will support the latest authentication and authorization techniques. 

NOTE: The Synchronizer itself is not affected and will process appointments without a problem

Temporary solution

For O365 users trying to link new users in the Synchronizer admin, there are two temporary solutions:

1. Use a workaround to link new users

The idea of this workaround is to add the users you want to link to the contact folder in O365 of the SyncUser (The user with the impersonation/Delegation rights).
How to add a contact can be seen in this video

  1. Add the new users (who you want to link) as contacts to the SyncUsers' contact folder in Outlook/O365
  2. Go to Sync admin > Technical Settings
  3. Remove the OAB URL 
  4. Click Apply this setting for all the users
  5. Go to User Synchronization Settings
  6. Click Load External users
  7. Click Ok on the pop-up message

It will now load the contacts which you have added to the SyncUsers' contact folder in Outlook/O365 and you can now link these users.

2. Update the Synchronizer version

We have a new version that uses a different technique to retrieve the addresses when Office 365 is used. This is a temporary update until we have released the new Synchronizer with the new authentication method.

The idea is to have a 2nd Synchronizer folder next to your current installation folder. When you want to link new user start the Sync admin from the 2nd folder, all the steps are explained below.

Note: This version is only available when you have SuperOffice 8.3R1 or higher

NOTE: Users with mixed configurations (Exchange on-premise and O365) can also use this version. We will use the new authentication method automatically when the OAB contains

The new version 3.2.296 can be downloaded here.
Notice that this is not a setup. But a zip file containing separate Synchronizer files.

How to install:

  1. Stop the Synchronizer service
  2. Make a copy of the current Synchronizer installation folder (C:\Program Files (x86)\InfoBridge\Exchange Online Synchronizer)
  3. Rename the copied folder to, for example, Exchange online Synchronizer - Link User version
  4. Download the zip file
  5. Unblock the zip file via right mouseclick -> properties (if needed)
  6. Unzip the file and copy all files to the copied installation folder from step 3
  7. Paste the files in the installation folder, overwrite existing files

How to use it:

  1. Start the Synchronizer admin from the copied folder
  2. Go to the User Synchronization Settings
  3. Click Load External Users
  4. An Authentication screen is started where you need to fill in the syncuser's email address
  5. Click Next
  6. In the next screen fill in the password of the SyncUser
  7. Click Next
  8. The Synchronizer will now try to locate the Global List Provider
  9. If successful, the list of users will be loaded and you can start linking the users.
    Note: When the list is not loaded (only a white screen is shown) close the synch admin and start it again. Or/and install Google Chrome on the server and make it default browser. It helped on a couple of occasions.
  10. After the new user(s) are linked you can start the Service again and run the Synchronizer.