Hi Christophe,
We suspect that you have referred the assemblies from the following location which is causing the problem,
C:\Program Files (x86)\Syncfusion\Essential Studio\14.2.0.26\Universal Windows\10.0\SDK\References\CommonConfiguration\neutral
Can you refer the assemblies from the below location and let us know the status?
C:\Program Files (x86)\Syncfusion\Essential Studio\14.2.0.26\Assemblies for Universal Windows\10.0
Also this exception is due to retrieving of localization resources file but, it is not possible to avoid this exception in WinRT/UWP platforms. But you can overcome this exception by including that resource file in your application/sample.
In the above sample, we have added the Resource file to avoid the exception.
You can get the default resource file from the below UG link,
Regards,
Jai Ganesh S