Exception to Login

hi Guys,

I am now desperately trying to get the sample running in Github Fork for a few days now.
Unfortunately, the big problem with the thing is that I get the error every time:

Unhandled exception occurred while processing the request.
XmlException: ‘.’, Hexadecimal value 0x00, is an invalid character. Line 1, position 1.
System.Xml.XmlTextReaderImpl.Throw (Exception e)

CryptographicException: An error occurred while trying to encrypt the provided data. Refer to the internal exception for more information.
Microsoft.AspNetCore.DataProtection.KeyManagement.KeyRingBasedDataProtector.Protect (Byte ] plaintext) “”

The exact error I add as an attachment because he is too long otherwise.
The settings are as standard as you get in Guthub Fork.
Only my app data is registered.

I hope there is a solution because we already use it successfully with a UWP app.
However, this should be followed by a website on a Linux server demnäch UWP would be important.
Thank you soo Mutch
[link text][1]

Which sample are you trying to run? Could you share a snippet of code from the failing authentication?