Hi there.
I started Arduino and got a crash in gtk-qt-engine 
(splash.png-gtk-tqt-application).
I just tried to upload a crash report but the upload failed with this 
message:

Your crash report failed to upload!
Please check your network settings and try again.
The server responded:
Invalid proof of work
This server requires a SHA1 difficulty of 14 to accept anonymous crash 
reports

I'm using the preliminary stable build on Stretch.

Regards,
Philip Ashmore