Password checking takes long even though it's not wrong

Question

I'm aware that there is an intended delay when entering a wrong password. However, since about yesterday, my Ubuntu 16.04 takes 10-20 seconds or sometimes even more to verify the password, even though it's the right one. That problem happens on the lock screen, it happens when I use sudo, it doesn't matter where I type in my password.

Does anybody have an idea why that might be the case?

Answer 1

Check your DNS settings. Sometimes it cannot resolve even localhost if the line is missing from /etc/hosts.