Legacy exchange dn in the "to" field in outlook

Description of the error:

When booking coexistence a meeting room in Planner, the meeting rooms outlook address is replaced with it's legacy exchange dn, for example

George Michael </o=[Our Domain]/ou=[Whatever User Group] (FYDIBOHF23SPDLT)/cn=Recipients/cn=gmichael> 

The error only happens with Exchange integrated meeting rooms.

Solution:

The problem is that the address book isn't updated. This is a Microsoft error, so Pronestor can't fix it.

But there are several guides online on how to fix this in outlook.

For example this link https://community.spiceworks.com/topic/1985480-outlook-2013-showing-legacyexchangedn

We have also used this fix to force outlook to update its address book:

• Close outlook
• Go to %userprofile%\AppData\Local\Microsoft\Outlook\ 
• Search for all .OAB files
• Delete all .OAB files
• Restart outlook