I just upgraded from Ubuntu 16.10 to 17.04 and I can not mount my LUKS partition anymore.
I had a power outage and this forced the reboot after the upgrade...
I executed chk_luks_keyslots and my LUKS header looks good but, when I type my password, I see:
"No key available with this passphrase."
I'm afraid that I just lost ~15 years of files... :-/
Let me know if it works for you! I'm about to downgrade to Ubuntu 16.10 (just a LiveCD session) and give it a try.