EWS and OAuth

Since world is moving towards Cloud and away from Basic authentication, I also have to address this in my scripts. With the latest announcement on The Microsoft Exchange Team Blog about the Upcoming changes to Exchange Web Services (EWS) API for Office 365, I get a lot of questions from people about this.

First of all: This change is ONLY for Office 365!

Besides this I appreciate this change and believe it or not with the latest Exchange versions you can use OAuth already on your on-premises environment.

In this post I describe how get your tokens using ADAL, which can be used for accessing a mailbox via EWS. Most of you might already used a tool, which supports OAuth, but weren’t aware of: EWS Editor

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Skype for Business and broken pictures

I just came across an issue with Skype for Business clients. The contact pictures are not shown. Even the own profile picture is empty:

Update 24.07.2018
Finally the root cause was found. Please read how we fixed it here on the bottom.

Exchange Online migration and TooManyBadItemsPermanetException

I’m sure that a lot of people have seen this issue before when migrating to Exchange Online:

The BadItemLimit was exceeded and therefore the move request failed.

A while a go Ben Winzenz wrote an excellent post on the You Had Me At EHLO blog, where he mentioned that there was a change in Exchange Online and now failed mapping of SIDs will count towards the BadItemLimit.

So far so good, but how do we solve such issues when increasing of bad item limit is not an option and you have to migrate approx. 130.000 mailboxes?

Get-AutoDV2

In my previous post Troubleshooting Autodiscover I wrote about Autodiscover service and the difference between POX and SOAP requests. Over the last years Microsoft evolved Autodiscover and introduced a new Autodiscover service V2. The new version is based on JSON and the main difference is the fact you don’t need to be authenticated.

EXO migration and NotAcceptedDomainException in Hybrid

When it comes to Exchange Online migration and you have a lot of SMTP namespace, you might run into issues

• when you’re trying to migrate the user
• when you try to grant Send As permissions

Office 365 Exchange Hybrid: When Autodiscover and legacy PF impacting Outlook performance

I spent last weeks quite some time with Outlook performance issues in an Exchange Hybrid scenario. In addition this is not a normal Hybrid as here multiple Exchange Organizations from different AD Forests without any Trust Relationships are involved.

Thus I’m not talking about the scenario described in TechNet Multi-forest hybrid deployment scenario. It looks more like this:

Deep dive:Exchange Online PowerShell and MFA

When you read the headline, you’re might thinking “Oh no! Another post about this topic!”. But I think this post is worth reading as I’ll go deep into details.

Over the last months I have seen an increase of questions from various teammates and other teams in regards of the Exchange Online Remote PowerShell Module. The questions where mostly related to connectivity issue and prompts for re-authentication as PSSessions got into a broken state.

Also the fact that in some areas a proxy needs to be used, might be confusing as well as the question what to do if you have a service account or want to use the module in ISE.