My liferea version is liferea-1.8.5-1.fc16.x86_64
I have a hosted tt-rss instance, as well as trying the http://online.tt-rss.org instance. In both cases, the sync doesn't work. No feeds show up.
In my hosted instance, I use https://, whereas for the online version I use http://.
The version of tt-rss in both cases is from the tt-rss git repo, which is slightly newer than the 1.5.11 release.