Ubuntu с Netatalk и Samba TimeMachine не может соединиться

You can get more info on the issue with the debug log of afpd (Apple Filing Protocol daemon, part of netatalk package). To obtain it, add the following to configuration line in afpd.conf (it's usually located at the bottom of the file):

-setuplog "default log_debug /var/log/afpd.log"

E.g., my config line looks like this:

- -tcp -noddp -mimicmodel TimeCapsule6,106 -uamlist uams_dhx2.so -setuplog "default log_debug /var/log/afpd.log"

After that, restart netatalk service and try to connect to your server from a mac. The /var/log/afpd.log now contain a lot of useful info for resolving the issue. Also, please provide contents of your afpd.conf and AppleVolumes.default (without commented lines, cause there are a lot of it). Mentioned files located in /etc/netatalk, at least in Archlinux.