Most AV "web" shields interfere with connectivity when a solid firewall is used. They're competing for resources against the firewall, and this typically results in problems.
I can't believe in such non-sense...

yup that sure is the problem i uninstalled comodo firewall and no problems at all
You did not solve, just run away from the problem.
Comodo last stable version is running perfectly with avast here.
I tend to stay away from beta releases for something as important as my firewall
I'm not that prudent as David. But in this case, I fully agree. Beta releases of Comodo could be a nightmare. In general, beta releases of a firewall are a nightmare.