Tor stops at establishing encrypted directory connection

I try to run Tor v0.2.1.27 behind a strict firewall setup. I have access to http/https via a proxy which I entered into into the tor settings. All other ports are blocked by the firewall. I also said inside the settings, that i can only connect to port 443 and i added a couple of tor bridges. Please take a look the attached screenshot.

But besides all that. When Tor starts up I see a couple of things happening, but when Tor says "establishing encrypted directory connection" the progress bar stops. Inside the log i can find this entries...

Dez 20 12:30:02.559 [Notice] Tor v0.2.1.27 ([changeset:e57cb6b9762a2f94 re57cb6b9762a2f94]). This is experimental software. Do not rely on it for strong anonymity. (Running on Very recent version of Windows [major=6,minor=1]  [workstation] {terminal services, single user})
Dez 20 12:30:02.559 [Notice] Initialized libevent version 1.4.14-stable using method win32. Good.
Dez 20 12:30:02.559 [Notice] Opening Socks listener on 127.0.0.1:9050
Dez 20 12:30:02.559 [Notice] Opening Control listener on 127.0.0.1:9051
Dez 20 12:30:02.559 [Notice] Parsing GEOIP file.
Dez 20 12:31:48.534 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:31:59.534 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:32:10.535 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:32:16.535 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:32:21.536 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:32:32.536 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:32:43.537 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:32:54.538 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:33:05.538 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:33:16.539 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:33:17.539 [Info] should_delay_dir_fetches(): delaying dir fetches (no running bridges known)
Dez 20 12:33:23.376 [Debug] conn_read_callback(): socket 476 wants to read.
Dez 20 12:33:23.377 [Debug] conn_read_callback(): socket 476 wants to read.

Trac:
Username: Chrissss