I don't see any errors on the logs but the relay is always showing in the relay search page as down. I even tried to upgrade the Tor client to a new version 0.4.6.10 to see if something changes, but no success.
The process is running all the time, I see some circuit connections forming and after a while no more traffic going.
Based on the syslog I see that everything looks fine, see next example.
Apr 18 20:32:17 ubu01 Tor[1093]: Bootstrapped 10% (conn_done): Connected to a relay
Apr 18 20:32:17 ubu01 Tor[1093]: Bootstrapped 14% (handshake): Handshaking with a relay
Apr 18 20:32:18 ubu01 Tor[1093]: Bootstrapped 15% (handshake_done): Handshake with a relay done
Apr 18 20:32:18 ubu01 Tor[1093]: Bootstrapped 75% (enough_dirinfo): Loaded enough directory info to build circuits
Apr 18 20:32:18 ubu01 Tor[1093]: Bootstrapped 90% (ap_handshake_done): Handshake finished with a relay to build circuits
Apr 18 20:32:18 ubu01 Tor[1093]: Bootstrapped 95% (circuit_create): Establishing a Tor circuit
Apr 18 20:32:19 ubu01 Tor[1093]: Bootstrapped 100% (done): Done
Apr 18 20:32:54 ubu01 Tor[1093]: New control connection opened.
Apr 18 20:37:51 ubu01 Tor[1093]: External address seen and suggested by a directory authority: 187.74.71.95
Apr 18 20:38:17 ubu01 Tor[1093]: Now checking whether IPv4 ORPort
187.74.71.95:9001 is reachable... (this may take up to 20 minutes -- look for log messages indicating success)
Apr 18 20:39:20 ubu01 Tor[1093]: Self-testing indicates your ORPort
187.74.71.95:9001 is reachable from the outside. Excellent. Publishing server descriptor.
Apr 18 20:40:27 ubu01 Tor[1093]: New control connection opened.
Apr 18 20:42:20 ubu01 Tor[1093]: Performing bandwidth self-test...done.
I tried to test my income connection from another computer to validate that there was no block on the ISP side, I could connect successfully to port 9001 as indicated on the logs.