I updated my Windows today and encountered an error. I couldn't download symbols. I searched for a solution and found it in the ReadMe.txt file in the DWMBlurGlass applications folder.
In the ReadMe.txt file, the developer stated, "If you can't download the symbols, please use a proxy. The symbol server is a Microsoft server and may be walled off in some areas.".
To resolve this, I connected to my VPN and downloaded the symbols.
DWMBlurGlass is now working perfectly on my computer.
Have a great day :)