UFW is active but not enabled why?

mateusz@debian:~$ sudo ufw disable
Firewall stopped and disabled on system startup

mateusz@debian:~$ sudo ufw status verbose
Status: inactive

mateusz@debian:~$ sudo ufw enable
ERROR: problem running ufw-init

Even if error occurs, you can check that ufw is running.

mateusz@debian:~$ sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing)
New profiles: skip

To                         Action      From
--                         ------      ----
80/tcp                     ALLOW IN    Anywhere
22/tcp                     ALLOW IN    Anywhere

or

mateusz@debian:~$ sudo service ufw status
[ ok all is running...done.

You can easily set up manually ENABLED=yes in ufw config

sudo nano /etc/ufw/ufw.conf

which contains:

# /etc/ufw/ufw.conf
#

# Set to yes to start on boot. If setting this remotely, be sure to add a rule
# to allow your remote connection before starting ufw. Eg: 'ufw allow 22/tcp'
ENABLED=no

# Please use the 'ufw' command to set the loglevel. Eg: 'ufw logging medium'.
# See 'man ufw' for details.
LOGLEVEL=low

Setting ENABLED=yes in /etc/ufw/ufw.conf did it for me.

$ sudo ufw reload
Firewall not enabled (skipping reload)
$ sudo ufw logging on (showing that @Thomas' solution has no effect for me)
Logging enabled
$ sudo sed -ie 's/ENABLED=no/ENABLED=yes/' /etc/ufw/ufw.conf

Check to be sure that port 22 is enabled before you reload

$ sudo ufw status
Status: active

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW       Anywhere                  

Reload

$ sudo ufw reload
Firewall reloaded