Created attachment 140630 [details]
gdb backtrace of segfault

SUMMARY
At least some accounts of outlook.com do have one element in MeContact.
(tested with two separated accounts, same behavior).
On trying to sync this element a Segmentation Fault occurs.
This Segmentation Fault appears only if the element is not locally available already.


STEPS TO REPRODUCE
1. Create an outlook.com account.
   Account must have one element in MeContact (element type EwsItemTypeItem or 0)
2. Add account to Akonadi.
3. Open akonadiconsole and synchronize all elements of the resource.

OBSERVED RESULT
As soon as the synchronizing process tries to sync MeContact a
Segmentation Fault occurs.

EXPECTED RESULT
No Segmentation Faults at all.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Arch Linux Kernel 5.1.9-arch1-1
(available in About System)
KDE Plasma Version: 5.22.4
KDE Frameworks Version: 5.84.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
I'm no expert at this (RF Engineer) but I was able to find this log message
org.kde.pim.ews: "Could not find handler for item type 0"
after which a nullptr is returned.
So I thought maybe someone tries to access this nullptr.
I managed to make a debug build and get gdb to work.
back trace is attached.
In ewsfetchitemsjob.cpp:300 we can find this:
QString mimeType = EwsItemHandler::itemHandler(type)->mimeType();
As I understand it EwsItemTypeItem does not have a itemHandler and therefor
creating it returns a nullptr and calling mimeType() gets me a Segmentation Fault. To prevent it I tested an addition where I firstly check if there is a
nullptr and skip the element if itemHanlder(type) returns nullptr.
This removed the issue.