I built WireGuard from source, and I got "Module verification failed"
message when I tried to run "wg-quick up".
Here is what I found in dmesg:

[   55.700967] wireguard: module verification failed: signature and/or
required key missing - tainting kernel[   55.701390] wireguard: WireGuard 0.0.20170810 loaded. See
www.wireguard.com for information.[   55.701391] wireguard: Copyright (C) 2015-2017 Jason A. Donenfeld
<Jason@zx2c4.com>. All Rights Reserved.
ffs@server:~$ uname -a
Linux server 4.4.0-93-generic #116-Ubuntu SMP Fri Aug 11 21:17:51 UTC
2017 x86_64 x86_64 x86_64 GNU/Linux
Thanks!