See issue here as well: https://forum.fopnu.com/support/46
I believe you are talking about being unable to launch fopnu after installing and it is not related to being unable to download a file?
You are not alone - here is what happened essentially:
"I had the exact same issue happen with Tixati (twice)- where it was automatically uninstalled and this week after running fopnu for nearly 6 months it was uninstalled upon a reboot automatically with no warning.
Fortunately when you re-install, the configurations are restored and not reset."
Solution: Reinstall the program