upgrade fail from 3.9 to 5.0

I tried to upgrade my version from 3.9 to 5.0 and got the following log details (see below and stopped at 20% complete). I used the upgrader on the backend after entering my API key.

Installed version: 3.9.19775
Latest available version: 5.0.190000

Log details
Starting upgrade process ...
Downloading patch files ...
Updating Foundry Framework
Extracting patch files ...
MD5 checksum for downloaded file does not match ...